In addition to revealing its roadmap and plans concerning its current leading-edge process technologies, TSMC also shared progress of its N2 node as part of its Symposiums 2024. The company's first 2nm-class fabrication node, and predominantly featuring gate-all-around transistors, according to TSMC N2 has almost achieved its target performance and yield goals, which places it on track to enter high-volume manufacturing in the second half of 2025.
TSMC states that 'N2 development is well on track and N2P is next.' In particular, gate-all-around nanosheet devices currently achieve over 90% of their expected performance, whereas yields of 256 Mb SRAM (32 MB) devices already exceeds 80%, depending on the batch. All of this for a node that is over a year away from mass production.
Meanwhile, average yield of a 256 Mb SRAM was around 70% as of March, 2024, up from around 35% in April, 2023. Device performance has also been improving with higher frequencies being achieved while keeping power consumption in check.
Chip designer interest towards TSMC's first 2nm-class gate-all-around nanosheet transistor-based technology is significant, too. The number of new tape-outs (NTOs) in the first year of N2 is over two-times higher than it was for N5. Though with that said, given TSMC's close working relationship with a handful of high-volume vendors – most notably Appe – NTOs can be a very misleading figure since the first year of a new node at TSMC is capacity constrained, and consequently the bulk of that capacity goes to TSMC's priority partners.
Meanwhile, there were considerably more N5 tapeouts in its second year (some where N5P, of course) and N2 promises to have 2.6X more NTOs in its second year. So the node indeed looks quite promising. In fact, based on TSMC's slides (which we're unfortunately not able to republish), N2 is more popular than N3 in terms of NTOs both in the first and the second years of existence.
When it comes to the second year of N2, in the second half of 2026 TSMC plans to roll out its N2P technology, which promises additional performance and power benefits. N2P is expected to improve frequency by 15% - 20%, reduce power consumption by 30% - 40%, and increase chip density by over 1.15 times compared to N3E, significant benefits to move to all-new GAA nanosheet transistors.
Finally, for those companies that need the best in performance, power, and density, TSMC is poised to offer their A16 process in 2026. That node will also bring in backside power delivery, which will add costs, but is expected to greatly improve performance efficiency and scaling.
SemiconductorsKioxia's booth at FMS 2024 was a busy one with multiple technology demonstrations keeping visitors occupied. A walk-through of the BiCS 8 manufacturing process was the first to grab my attention. Kioxia and Western Digital announced the sampling of BiCS 8 in March 2023. We had touched briefly upon its CMOS Bonded Array (CBA) scheme in our coverage of Kioxial's 2Tb QLC NAND device and coverage of Western Digital's 128 TB QLC enterprise SSD proof-of-concept demonstration. At Kioxia's booth, we got more insights.
Traditionally, fabrication of flash chips involved placement of the associate logic circuitry (CMOS process) around the periphery of the flash array. The process then moved on to putting the CMOS under the cell array, but the wafer development process was serialized with the CMOS logic getting fabricated first followed by the cell array on top. However, this has some challenges because the cell array requires a high-temperature processing step to ensure higher reliability that can be detrimental to the health of the CMOS logic. Thanks to recent advancements in wafer bonding techniques, the new CBA process allows the CMOS wafer and cell array wafer to be processed independently in parallel and then pieced together, as shown in the models above.
The BiCS 8 3D NAND incorporates 218 layers, compared to 112 layers in BiCS 5 and 162 layers in BiCS 6. The company decided to skip over BiCS 7 (or, rather, it was probably a short-lived generation meant as an internal test vehicle). The generation retains the four-plane charge trap structure of BiCS 6. In its TLC avatar, it is available as a 1 Tbit device. The QLC version is available in two capacities - 1 Tbit and 2 Tbit.
Kioxia also noted that while the number of layers (218) doesn't compare favorably with the latest layer counts from the competition, its lateral scaling / cell shrinkage has enabled it to be competitive in terms of bit density as well as operating speeds (3200 MT/s). For reference, the latest shipping NAND from Micron - the G9 - has 276 layers with a bit density in TLC mode of 21 Gbit/mm2, and operates at up to 3600 MT/s. However, its 232L NAND operates only up to 2400 MT/s and has a bit density of 14.6 Gbit/mm2.
It must be noted that the CBA hybrid bonding process has advantages over the current processes used by other vendors - including Micron's CMOS under array (CuA) and SK hynix's 4D PUC (periphery-under-chip) developed in the late 2010s. It is expected that other NAND vendors will also move eventually to some variant of the hybrid bonding scheme used by Kioxia.
StorageWhile the bulk of attention on TSMC is aimed at its leading-edge nodes, such as N3E and N2, loads of chips will continue to be made using more mature and proven process technologies for years to come. Which is why TSMC has continued to refine its existing nodes, including its current-generation 5nm-class offerings. To that end, at its North American Technology Symposium 2024, the company introduced a new, optimized 5nm-class node: N4C.
TSMC's N4C process belongs to the company's 5nm-class family of fab nodes and is a superset of N4P, the most advanced technology in that family. In a bid to further bring down 5nm manufacturing costs, for TSMC is implementing several changes for N4C, including rearchitecting their standard cell and SRAM cell, changing some design rules, and reducing the number of masking layers. As a result of these improvements, the company expects N4C to achieve both smaller die sizes as well as a reduction in production complexity, which in turn will bring die costs down by up to 8.5%. Furthermore, with the same wafer-level defect density rate as N4P, N4C stands to offer even higher functional yields thanks to its die area reduction.
"So, we are not done with our 5nm and 4nm [technologies]," said Kevin Zhang, Vice President of Business Development at TSMC. "From N5 to N4, we have achieved 4% density improvement optical shrink, and we continue to enhance the transistor performance. Now we bring in N4C to our 4 nm technology portfolio. N4C allows our customers to reduce their costs by remove some of the masks and to also improve on the original IP design like a standard cell and SRAM to further reduce the overall product level cost of ownership."
TSMC says that N4C can use the same design infrastructure as N4P, though it is unclear whether N5 and N4P IP can be re-used for N4C-based chips. Meanwhile, TSMC indicates that it offers various options for chipmakers to find the right balance between cost benefits and design effort, so companies interested in adopting a 4nm-class process technologies could well adopt N4C.
The development of N4C comes as many of TSMC's chip design customers are preparing to launch chips based on the company's final generation of FinFET process technology, the 3nm N3 series. While N3 is expected to be a successful family, the high costs of N3B have been an issue, and the generation is marked by diminishing performance and transistor density returns altogether. Consequently, N4C could well become a major, long-lived node at TSMC, serving as a good fit for customers who want to stick to a more cost-effective FinFET node.
"This is a very significant enhancement, we are working with our customer, basically to extract more value from their 4 nm investment," Zhang said.
TSMC expects to start volume production of N4C chips some time next year. And with TSMC having produced 5nm-class for nearly half a decade at that point, N4C should be able to hit the ground running in terms of volume and yields.
When Western Digital introduced its Ultrastar DC SN861 SSDs earlier this year, the company did not disclose which controller it used for these drives, which made many observers presume that WD was using an in-house controller. But a recent teardown of the drive shows that is not the case; instead, the company is using a controller from Fadu, a South Korean company founded in 2015 that specializes on enterprise-grade turnkey SSD solutions.
The Western Digital Ultrastar DC SN861 SSD is aimed at performance-hungry hyperscale datacenters and enterprise customers which are adopting PCIe Gen5 storage devices these days. And, as uncovered in photos from a recent Storage Review article, the drive is based on Fadu's FC5161 NVMe 2.0-compliant controller. The FC5161 utilizes 16 NAND channels supporting an ONFi 5.0 2400 MT/s interface, and features a combination of enterprise-grade capabilities (OCP Cloud Spec 2.0, SR-IOV, up to 512 name spaces for ZNS support, flexible data placement, NVMe-MI 1.2, advanced security, telemetry, power loss protection) not available on other off-the-shelf controllers – or on any previous Western Digital controllers.
The Ultrastar DC SN861 SSD offers sequential read speeds up to 13.7 GB/s as well as sequential write speeds up to 7.5 GB/s. As for random performance, it boasts with an up to 3.3 million random 4K read IOPS and up to 0.8 million random 4K write IOPS. The drives are available in capacities between 1.6 TB and 7.68 TB with one or three drive writes per day (DWPD) over five years rating as well as in U.2 and E1.S form-factors.
While the two form factors of the SN861 share a similar technical design, Western Digital has tailored each version for distinct workloads: the E1.S supports FDP and performance enhancements specifically for cloud environments. By contrast, the U.2 model is geared towards high-performance enterprise tasks and emerging applications like AI.
Without any doubts, Western Digital's Ultrastar DC SN861 is a feature-rich high-performance enterprise-grade SSD. It has another distinctive feature: a 5W idle power consumption, which is rather low by the standards of enterprise-grade drives (e.g., it is 1W lower compared to the SN840). While the difference with predecessors may be just 1W, hyperscalers deploy thousands of drives and for their TCO every watt counts.
Western Digital's Ultrastar DC SN861 SSDs are now available for purchase to select customers (such as Meta) and to interested parties. Prices are unknown, but they will depend on such factors as volumes.
Sources: Fadu, Storage Review
StorageKioxia's booth at FMS 2024 was a busy one with multiple technology demonstrations keeping visitors occupied. A walk-through of the BiCS 8 manufacturing process was the first to grab my attention. Kioxia and Western Digital announced the sampling of BiCS 8 in March 2023. We had touched briefly upon its CMOS Bonded Array (CBA) scheme in our coverage of Kioxial's 2Tb QLC NAND device and coverage of Western Digital's 128 TB QLC enterprise SSD proof-of-concept demonstration. At Kioxia's booth, we got more insights.
Traditionally, fabrication of flash chips involved placement of the associate logic circuitry (CMOS process) around the periphery of the flash array. The process then moved on to putting the CMOS under the cell array, but the wafer development process was serialized with the CMOS logic getting fabricated first followed by the cell array on top. However, this has some challenges because the cell array requires a high-temperature processing step to ensure higher reliability that can be detrimental to the health of the CMOS logic. Thanks to recent advancements in wafer bonding techniques, the new CBA process allows the CMOS wafer and cell array wafer to be processed independently in parallel and then pieced together, as shown in the models above.
The BiCS 8 3D NAND incorporates 218 layers, compared to 112 layers in BiCS 5 and 162 layers in BiCS 6. The company decided to skip over BiCS 7 (or, rather, it was probably a short-lived generation meant as an internal test vehicle). The generation retains the four-plane charge trap structure of BiCS 6. In its TLC avatar, it is available as a 1 Tbit device. The QLC version is available in two capacities - 1 Tbit and 2 Tbit.
Kioxia also noted that while the number of layers (218) doesn't compare favorably with the latest layer counts from the competition, its lateral scaling / cell shrinkage has enabled it to be competitive in terms of bit density as well as operating speeds (3200 MT/s). For reference, the latest shipping NAND from Micron - the G9 - has 276 layers with a bit density in TLC mode of 21 Gbit/mm2, and operates at up to 3600 MT/s. However, its 232L NAND operates only up to 2400 MT/s and has a bit density of 14.6 Gbit/mm2.
It must be noted that the CBA hybrid bonding process has advantages over the current processes used by other vendors - including Micron's CMOS under array (CuA) and SK hynix's 4D PUC (periphery-under-chip) developed in the late 2010s. It is expected that other NAND vendors will also move eventually to some variant of the hybrid bonding scheme used by Kioxia.
StorageWhile the bulk of attention on TSMC is aimed at its leading-edge nodes, such as N3E and N2, loads of chips will continue to be made using more mature and proven process technologies for years to come. Which is why TSMC has continued to refine its existing nodes, including its current-generation 5nm-class offerings. To that end, at its North American Technology Symposium 2024, the company introduced a new, optimized 5nm-class node: N4C.
TSMC's N4C process belongs to the company's 5nm-class family of fab nodes and is a superset of N4P, the most advanced technology in that family. In a bid to further bring down 5nm manufacturing costs, for TSMC is implementing several changes for N4C, including rearchitecting their standard cell and SRAM cell, changing some design rules, and reducing the number of masking layers. As a result of these improvements, the company expects N4C to achieve both smaller die sizes as well as a reduction in production complexity, which in turn will bring die costs down by up to 8.5%. Furthermore, with the same wafer-level defect density rate as N4P, N4C stands to offer even higher functional yields thanks to its die area reduction.
"So, we are not done with our 5nm and 4nm [technologies]," said Kevin Zhang, Vice President of Business Development at TSMC. "From N5 to N4, we have achieved 4% density improvement optical shrink, and we continue to enhance the transistor performance. Now we bring in N4C to our 4 nm technology portfolio. N4C allows our customers to reduce their costs by remove some of the masks and to also improve on the original IP design like a standard cell and SRAM to further reduce the overall product level cost of ownership."
TSMC says that N4C can use the same design infrastructure as N4P, though it is unclear whether N5 and N4P IP can be re-used for N4C-based chips. Meanwhile, TSMC indicates that it offers various options for chipmakers to find the right balance between cost benefits and design effort, so companies interested in adopting a 4nm-class process technologies could well adopt N4C.
The development of N4C comes as many of TSMC's chip design customers are preparing to launch chips based on the company's final generation of FinFET process technology, the 3nm N3 series. While N3 is expected to be a successful family, the high costs of N3B have been an issue, and the generation is marked by diminishing performance and transistor density returns altogether. Consequently, N4C could well become a major, long-lived node at TSMC, serving as a good fit for customers who want to stick to a more cost-effective FinFET node.
"This is a very significant enhancement, we are working with our customer, basically to extract more value from their 4 nm investment," Zhang said.
TSMC expects to start volume production of N4C chips some time next year. And with TSMC having produced 5nm-class for nearly half a decade at that point, N4C should be able to hit the ground running in terms of volume and yields.
When Western Digital introduced its Ultrastar DC SN861 SSDs earlier this year, the company did not disclose which controller it used for these drives, which made many observers presume that WD was using an in-house controller. But a recent teardown of the drive shows that is not the case; instead, the company is using a controller from Fadu, a South Korean company founded in 2015 that specializes on enterprise-grade turnkey SSD solutions.
The Western Digital Ultrastar DC SN861 SSD is aimed at performance-hungry hyperscale datacenters and enterprise customers which are adopting PCIe Gen5 storage devices these days. And, as uncovered in photos from a recent Storage Review article, the drive is based on Fadu's FC5161 NVMe 2.0-compliant controller. The FC5161 utilizes 16 NAND channels supporting an ONFi 5.0 2400 MT/s interface, and features a combination of enterprise-grade capabilities (OCP Cloud Spec 2.0, SR-IOV, up to 512 name spaces for ZNS support, flexible data placement, NVMe-MI 1.2, advanced security, telemetry, power loss protection) not available on other off-the-shelf controllers – or on any previous Western Digital controllers.
The Ultrastar DC SN861 SSD offers sequential read speeds up to 13.7 GB/s as well as sequential write speeds up to 7.5 GB/s. As for random performance, it boasts with an up to 3.3 million random 4K read IOPS and up to 0.8 million random 4K write IOPS. The drives are available in capacities between 1.6 TB and 7.68 TB with one or three drive writes per day (DWPD) over five years rating as well as in U.2 and E1.S form-factors.
While the two form factors of the SN861 share a similar technical design, Western Digital has tailored each version for distinct workloads: the E1.S supports FDP and performance enhancements specifically for cloud environments. By contrast, the U.2 model is geared towards high-performance enterprise tasks and emerging applications like AI.
Without any doubts, Western Digital's Ultrastar DC SN861 is a feature-rich high-performance enterprise-grade SSD. It has another distinctive feature: a 5W idle power consumption, which is rather low by the standards of enterprise-grade drives (e.g., it is 1W lower compared to the SN840). While the difference with predecessors may be just 1W, hyperscalers deploy thousands of drives and for their TCO every watt counts.
Western Digital's Ultrastar DC SN861 SSDs are now available for purchase to select customers (such as Meta) and to interested parties. Prices are unknown, but they will depend on such factors as volumes.
Sources: Fadu, Storage Review
StorageThe Ultra Ethernet Consortium (UEC) has announced this week that the next-generation interconnection consortium has grown to 55 members. And as the group works towards developing the initial version of their ultra-fast Ethernet standard, they have released some of the first technical details on the upcoming standard.
Formed in the summer of 2023, the UEC aims to develop a new standard for interconnection for AI and HPC datacenter needs, serving as a de-facto (if not de-jure) alternative to InfiniBand, which is largely under the control of NVIDIA these days. The UEC began to accept new members back in November, and just in five months' time it gained 45 new members, which highlights massive interest for the new technology. The consortium now boasts 55 members and 715 industry experts, who are working across eight technical groups.
There is a lot of work at hand for the UEC, as the group has laid out in their latest development blog post, as the consortium works to to build a unified Ethernet-based communication stack for high-performance networking supporting artificial intelligence and high-performance computing clusters. The consortium's technical objectives include developing specifications, APIs, and source code for Ultra Ethernet communications, updating existing protocols, and introducing new mechanisms for telemetry, signaling, security, and congestion management. In particular, Ultra Ethernet introduces the UEC Transport (UET) for higher network utilization and lower tail latency to speed up RDMA (Remote Direct Memory Access) operation over Ethernet. Key features include multi-path packet spraying, flexible ordering, and advanced congestion control, ensuring efficient and reliable data transfer.
These enhancements are designed to address the needs of large AI and HPC clusters — with separate profiles for each type of deployment — though everything is done in a surgical manner to enhance the technology, but reuse as much of the existing Ethernet as possible to maintain cost efficiency and interoperability.
The consortium's founding members include AMD, Arista, Broadcom, Cisco, Eviden (an Atos Business), HPE, Intel, Meta, and Microsoft. After the Ultra Ethernet Consortium (UEC) began to accept new members in October, 2023, numerous industry heavyweights have joined the group, including Baidu, Dell, Huawei, IBM, Nokia, Lenovo, Supermicro, and Tencent.
The consortium currently plans to release the initial 1.0 version of the UEC specification publicly sometime in the third quarter of 2024.
"There was always a recognition that UEC was meeting a need in the industry," said J Metz, Chair of the UEC Steering Committee. "There is a strong desire to have an open, accessible, Ethernet-based network specifically designed to accommodate AI and HPC workload requirements. This level of involvement is encouraging; it helps us achieve the goal of broad interoperability and stability."
While it is evident that then Ultra Ethernet Consortium is gaining support across the industry, it is still unclear where other industry behemoths like AWS and Google stand. While the hardware companies involved can design Ultra Ethernet support into their hardware and systems, the technology ultimately exists to serve large datacenter and HPC system operators. So it will be interesting to see what interest they take in (and how quickly they adopt) the nascent Ethernet backbone technology once hardware incorporating it is ready.
NetworkingIn addition to revealing its roadmap and plans concerning its current leading-edge process technologies, TSMC also shared progress of its N2 node as part of its Symposiums 2024. The company's first 2nm-class fabrication node, and predominantly featuring gate-all-around transistors, according to TSMC N2 has almost achieved its target performance and yield goals, which places it on track to enter high-volume manufacturing in the second half of 2025.
TSMC states that 'N2 development is well on track and N2P is next.' In particular, gate-all-around nanosheet devices currently achieve over 90% of their expected performance, whereas yields of 256 Mb SRAM (32 MB) devices already exceeds 80%, depending on the batch. All of this for a node that is over a year away from mass production.
Meanwhile, average yield of a 256 Mb SRAM was around 70% as of March, 2024, up from around 35% in April, 2023. Device performance has also been improving with higher frequencies being achieved while keeping power consumption in check.
Chip designer interest towards TSMC's first 2nm-class gate-all-around nanosheet transistor-based technology is significant, too. The number of new tape-outs (NTOs) in the first year of N2 is over two-times higher than it was for N5. Though with that said, given TSMC's close working relationship with a handful of high-volume vendors – most notably Appe – NTOs can be a very misleading figure since the first year of a new node at TSMC is capacity constrained, and consequently the bulk of that capacity goes to TSMC's priority partners.
Meanwhile, there were considerably more N5 tapeouts in its second year (some where N5P, of course) and N2 promises to have 2.6X more NTOs in its second year. So the node indeed looks quite promising. In fact, based on TSMC's slides (which we're unfortunately not able to republish), N2 is more popular than N3 in terms of NTOs both in the first and the second years of existence.
When it comes to the second year of N2, in the second half of 2026 TSMC plans to roll out its N2P technology, which promises additional performance and power benefits. N2P is expected to improve frequency by 15% - 20%, reduce power consumption by 30% - 40%, and increase chip density by over 1.15 times compared to N3E, significant benefits to move to all-new GAA nanosheet transistors.
Finally, for those companies that need the best in performance, power, and density, TSMC is poised to offer their A16 process in 2026. That node will also bring in backside power delivery, which will add costs, but is expected to greatly improve performance efficiency and scaling.
SemiconductorsWhile the bulk of attention on TSMC is aimed at its leading-edge nodes, such as N3E and N2, loads of chips will continue to be made using more mature and proven process technologies for years to come. Which is why TSMC has continued to refine its existing nodes, including its current-generation 5nm-class offerings. To that end, at its North American Technology Symposium 2024, the company introduced a new, optimized 5nm-class node: N4C.
TSMC's N4C process belongs to the company's 5nm-class family of fab nodes and is a superset of N4P, the most advanced technology in that family. In a bid to further bring down 5nm manufacturing costs, for TSMC is implementing several changes for N4C, including rearchitecting their standard cell and SRAM cell, changing some design rules, and reducing the number of masking layers. As a result of these improvements, the company expects N4C to achieve both smaller die sizes as well as a reduction in production complexity, which in turn will bring die costs down by up to 8.5%. Furthermore, with the same wafer-level defect density rate as N4P, N4C stands to offer even higher functional yields thanks to its die area reduction.
"So, we are not done with our 5nm and 4nm [technologies]," said Kevin Zhang, Vice President of Business Development at TSMC. "From N5 to N4, we have achieved 4% density improvement optical shrink, and we continue to enhance the transistor performance. Now we bring in N4C to our 4 nm technology portfolio. N4C allows our customers to reduce their costs by remove some of the masks and to also improve on the original IP design like a standard cell and SRAM to further reduce the overall product level cost of ownership."
TSMC says that N4C can use the same design infrastructure as N4P, though it is unclear whether N5 and N4P IP can be re-used for N4C-based chips. Meanwhile, TSMC indicates that it offers various options for chipmakers to find the right balance between cost benefits and design effort, so companies interested in adopting a 4nm-class process technologies could well adopt N4C.
The development of N4C comes as many of TSMC's chip design customers are preparing to launch chips based on the company's final generation of FinFET process technology, the 3nm N3 series. While N3 is expected to be a successful family, the high costs of N3B have been an issue, and the generation is marked by diminishing performance and transistor density returns altogether. Consequently, N4C could well become a major, long-lived node at TSMC, serving as a good fit for customers who want to stick to a more cost-effective FinFET node.
"This is a very significant enhancement, we are working with our customer, basically to extract more value from their 4 nm investment," Zhang said.
TSMC expects to start volume production of N4C chips some time next year. And with TSMC having produced 5nm-class for nearly half a decade at that point, N4C should be able to hit the ground running in terms of volume and yields.
Nowadays highest-capacity hard drives are typically aimed at cloud service providers (CSPs) and enterprises, but this does not mean that creative professionals or regular users do not need them. To cater to demands of more regular consumers, Western Digital has started shipments of its Red Pro 24 TB HDDs, which are aimed at high-end NAS use for creative professionals with significant storage requirements.
Western Digital's Red Pro 24 TB hard drives come approximately 20 months after their 22 TB model hit retail in 2022, offering an incremental improvement to WD's highest-capacity NAS and consumer hard drive offering. The platform uses conventional magnetic recording (CMR), feature a 7200 RPM rotating speed, are equipped with a 512 MB cache, and use OptiNAND technology to improve reliability as well as optimize performance and power consumption. The HDDs are rated for an up to 287 MB/s media to cache transfer rate, which makes them some of the fastest hard drives around (albeit, still a bit slower compared to CSP and enterprise-oriented HDDs).
Just like other high-end network-attached storage-aimed HDDs, the Red Pro 24 TB hard drives use helium-filled platforms that are very similar to those designed for enterprise drives. Consequently, the Red Pro 24 TB HDD are equipped with rotation vibration sensors to anticipate and proactively counteract disturbances caused by increased vibration and multi-axis shock sensors to detect subtle shock events and automatically offset them with dynamic fly height technology to ensure that heads to not scratch disks.
UPDATE 4/2/2024: Western Digital has notified us that WD Red Pro fully support ArmorCache capability, even though it is not listed in datasheets.
What these drives lack compared Apparently, just like WD Gold and Ultraster 22 TB and 24 TB drives for enterprises and cloud datacenters, WD Red Pro HDDs fully support the ArmorCache feature that provides protection against power loss when write-cache is enabled (WCE mode) and enhances performance when write-cache is disabled (WCD mode).
On the reliability side of matters, Western Digital's Red Pro 24 TB HDDs are designed for 24/7 operation in vibrating environments, such as enterprise-grade NAS with loads of bays, and are rated for up to 550 TB/year workloads as well as up to 600,000 load/unload cycles, which is in line with what Western Digital's WD Gold and Ultrastar hard drives offer.
As for power consumption, the WD Red Pro 24 TB consumes up to 6.4W during read and write operations, up to 3.9W in idle mode, and up to 1.2W in standby/sleep mode.
Western Digital's Red Pro 24 TB (WD240KFGX) HDDs are now shipping to resellers as well as NAS makers, and are slated to be available shortly. Expect these hard drives to be slightly cheaper than the WD Gold 24 TB model.
StorageG.Skill on Tuesday introduced its ultra-low-latency DDR5-6400 memory modules that feature a CAS latency of 30 clocks, which appears to be the industry's most aggressive timings yet for DDR5-6400 sticks. The modules will be available for both AMD and Intel CPU-based systems.
With every new generation of DDR memory comes an increase in data transfer rates and an extension of relative latencies. While for the vast majority of applications, the increased bandwidth offsets the performance impact of higher timings, there are applications that favor low latencies. However, shrinking latencies is sometimes harder than increasing data transfer rates, which is why low-latency modules are rare.
Nonetheless, G.Skill has apparently managed to cherry-pick enough DDR5 memory chips and build appropriate printed circuit boards to produce DDR5-6400 modules with CL30 timings, which are substantially lower than the CL46 timings recommended by JEDEC for this speed bin. This means that while JEDEC-standard modules have an absolute latency of 14.375 ns, G.Skill's modules can boast a latency of just 9.375 ns – an approximately 35% decrease.
G.Skill's DDR5-6400 CL30 39-39-102 modules have a capacity of 16 GB and will be available in 32 GB dual-channel kits, though the company does not disclose voltages, which are likely considerably higher than those standardized by JEDEC.
The company plans to make its DDR5-6400 modules available both for AMD systems with EXPO profiles (Trident Z5 Neo RGB and Trident Z5 Royal Neo) and for Intel-powered PCs with XMP 3.0 profiles (Trident Z5 RGB and Trident Z5 Royal). For AMD AM5 systems that have a practical limitation of 6000 MT/s – 6400 MT/s for DDR5 memory (as this is roughly as fast as AMD's Infinity Fabric can operate at with a 1:1 ratio), the new modules will be particularly beneficial for AMD's Ryzen 7000 and Ryzen 9000-series processors.
G.Skill notes that since its modules are non-standard, they will not work with all systems but will operate on high-end motherboards with properly cooled CPUs.
The new ultra-low-latency memory kits will be available worldwide from G.Skill's partners starting in late August 2024. The company did not disclose the pricing of these modules, but since we are talking about premium products that boast unique specifications, they are likely to be priced accordingly.
MemoryKioxia's booth at FMS 2024 was a busy one with multiple technology demonstrations keeping visitors occupied. A walk-through of the BiCS 8 manufacturing process was the first to grab my attention. Kioxia and Western Digital announced the sampling of BiCS 8 in March 2023. We had touched briefly upon its CMOS Bonded Array (CBA) scheme in our coverage of Kioxial's 2Tb QLC NAND device and coverage of Western Digital's 128 TB QLC enterprise SSD proof-of-concept demonstration. At Kioxia's booth, we got more insights.
Traditionally, fabrication of flash chips involved placement of the associate logic circuitry (CMOS process) around the periphery of the flash array. The process then moved on to putting the CMOS under the cell array, but the wafer development process was serialized with the CMOS logic getting fabricated first followed by the cell array on top. However, this has some challenges because the cell array requires a high-temperature processing step to ensure higher reliability that can be detrimental to the health of the CMOS logic. Thanks to recent advancements in wafer bonding techniques, the new CBA process allows the CMOS wafer and cell array wafer to be processed independently in parallel and then pieced together, as shown in the models above.
The BiCS 8 3D NAND incorporates 218 layers, compared to 112 layers in BiCS 5 and 162 layers in BiCS 6. The company decided to skip over BiCS 7 (or, rather, it was probably a short-lived generation meant as an internal test vehicle). The generation retains the four-plane charge trap structure of BiCS 6. In its TLC avatar, it is available as a 1 Tbit device. The QLC version is available in two capacities - 1 Tbit and 2 Tbit.
Kioxia also noted that while the number of layers (218) doesn't compare favorably with the latest layer counts from the competition, its lateral scaling / cell shrinkage has enabled it to be competitive in terms of bit density as well as operating speeds (3200 MT/s). For reference, the latest shipping NAND from Micron - the G9 - has 276 layers with a bit density in TLC mode of 21 Gbit/mm2, and operates at up to 3600 MT/s. However, its 232L NAND operates only up to 2400 MT/s and has a bit density of 14.6 Gbit/mm2.
It must be noted that the CBA hybrid bonding process has advantages over the current processes used by other vendors - including Micron's CMOS under array (CuA) and SK hynix's 4D PUC (periphery-under-chip) developed in the late 2010s. It is expected that other NAND vendors will also move eventually to some variant of the hybrid bonding scheme used by Kioxia.
StorageWhile the bulk of attention on TSMC is aimed at its leading-edge nodes, such as N3E and N2, loads of chips will continue to be made using more mature and proven process technologies for years to come. Which is why TSMC has continued to refine its existing nodes, including its current-generation 5nm-class offerings. To that end, at its North American Technology Symposium 2024, the company introduced a new, optimized 5nm-class node: N4C.
TSMC's N4C process belongs to the company's 5nm-class family of fab nodes and is a superset of N4P, the most advanced technology in that family. In a bid to further bring down 5nm manufacturing costs, for TSMC is implementing several changes for N4C, including rearchitecting their standard cell and SRAM cell, changing some design rules, and reducing the number of masking layers. As a result of these improvements, the company expects N4C to achieve both smaller die sizes as well as a reduction in production complexity, which in turn will bring die costs down by up to 8.5%. Furthermore, with the same wafer-level defect density rate as N4P, N4C stands to offer even higher functional yields thanks to its die area reduction.
"So, we are not done with our 5nm and 4nm [technologies]," said Kevin Zhang, Vice President of Business Development at TSMC. "From N5 to N4, we have achieved 4% density improvement optical shrink, and we continue to enhance the transistor performance. Now we bring in N4C to our 4 nm technology portfolio. N4C allows our customers to reduce their costs by remove some of the masks and to also improve on the original IP design like a standard cell and SRAM to further reduce the overall product level cost of ownership."
TSMC says that N4C can use the same design infrastructure as N4P, though it is unclear whether N5 and N4P IP can be re-used for N4C-based chips. Meanwhile, TSMC indicates that it offers various options for chipmakers to find the right balance between cost benefits and design effort, so companies interested in adopting a 4nm-class process technologies could well adopt N4C.
The development of N4C comes as many of TSMC's chip design customers are preparing to launch chips based on the company's final generation of FinFET process technology, the 3nm N3 series. While N3 is expected to be a successful family, the high costs of N3B have been an issue, and the generation is marked by diminishing performance and transistor density returns altogether. Consequently, N4C could well become a major, long-lived node at TSMC, serving as a good fit for customers who want to stick to a more cost-effective FinFET node.
"This is a very significant enhancement, we are working with our customer, basically to extract more value from their 4 nm investment," Zhang said.
TSMC expects to start volume production of N4C chips some time next year. And with TSMC having produced 5nm-class for nearly half a decade at that point, N4C should be able to hit the ground running in terms of volume and yields.
When Western Digital introduced its Ultrastar DC SN861 SSDs earlier this year, the company did not disclose which controller it used for these drives, which made many observers presume that WD was using an in-house controller. But a recent teardown of the drive shows that is not the case; instead, the company is using a controller from Fadu, a South Korean company founded in 2015 that specializes on enterprise-grade turnkey SSD solutions.
The Western Digital Ultrastar DC SN861 SSD is aimed at performance-hungry hyperscale datacenters and enterprise customers which are adopting PCIe Gen5 storage devices these days. And, as uncovered in photos from a recent Storage Review article, the drive is based on Fadu's FC5161 NVMe 2.0-compliant controller. The FC5161 utilizes 16 NAND channels supporting an ONFi 5.0 2400 MT/s interface, and features a combination of enterprise-grade capabilities (OCP Cloud Spec 2.0, SR-IOV, up to 512 name spaces for ZNS support, flexible data placement, NVMe-MI 1.2, advanced security, telemetry, power loss protection) not available on other off-the-shelf controllers – or on any previous Western Digital controllers.
The Ultrastar DC SN861 SSD offers sequential read speeds up to 13.7 GB/s as well as sequential write speeds up to 7.5 GB/s. As for random performance, it boasts with an up to 3.3 million random 4K read IOPS and up to 0.8 million random 4K write IOPS. The drives are available in capacities between 1.6 TB and 7.68 TB with one or three drive writes per day (DWPD) over five years rating as well as in U.2 and E1.S form-factors.
While the two form factors of the SN861 share a similar technical design, Western Digital has tailored each version for distinct workloads: the E1.S supports FDP and performance enhancements specifically for cloud environments. By contrast, the U.2 model is geared towards high-performance enterprise tasks and emerging applications like AI.
Without any doubts, Western Digital's Ultrastar DC SN861 is a feature-rich high-performance enterprise-grade SSD. It has another distinctive feature: a 5W idle power consumption, which is rather low by the standards of enterprise-grade drives (e.g., it is 1W lower compared to the SN840). While the difference with predecessors may be just 1W, hyperscalers deploy thousands of drives and for their TCO every watt counts.
Western Digital's Ultrastar DC SN861 SSDs are now available for purchase to select customers (such as Meta) and to interested parties. Prices are unknown, but they will depend on such factors as volumes.
Sources: Fadu, Storage Review
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