Samsung had quietly launched its BM1743 enterprise QLC SSD last month with a hefty 61.44 TB SKU. At FMS 2024, the company had the even larger 122.88 TB version of that SSD on display, alongside a few recorded benchmarking sessions. Compared to the previous generation, the BM1743 comes with a 4.1x improvement in I/O performance, improvement in data retention, and a 45% improvement in power efficiency for sequential writes.
The 128 TB-class QLC SSD boasts of sequential read speeds of 7.5 GBps and write speeds of 3 GBps. Random reads come in at 1.6 M IOPS, while 16 KB random writes clock in at 45K IOPS. Based on the quoted random write access granularity, it appears that Samsung is using a 16 KB indirection unit (IU) to optimize flash management. This is similar to the strategy adopted by Solidigm with IUs larger than 4K in their high-capacity SSDs.
A recorded benchmark session on the company's PM9D3a 8-channel Gen 5 SSD was also on display.
The SSD family is being promoted as a mainstream option for datacenters, and boasts of sequential reads up to 12 GBps and writes up to 6.8 GBps. Random reads clock in at 2 M IOPS, and random writes at 400 K IOPS.
Available in multiple form-factors up to 32 TB (M.2 tops out at 2 TB), the drive's firmware includes optional support for flexible data placement (FDP) to help address the write amplification aspect.
The PM1753 is the current enterprise SSD flagship in Samsung's lineup. With support for 16 NAND channels and capacities up to 32 TB, this U.2 / E3.S SSD has advertised sequential read and write speeds of 14.8 GBps and 11 GBps respectively. Random reads and writes for 4 KB accesses are listed at 3.4 M and 600 K IOPS.
Samsung claims a 1.7x performance improvement and a 1.7x power efficiency improvement over the previous generation (PM1743), making this TLC SSD suitable for AI servers.
The 9th Gen. V-NAND wafer was also available for viewing, though photography was prohibited. Mass production of this flash memory began in April 2024.
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.
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.
StorageThe CXL consortium has had a regular presence at FMS (which rechristened itself from 'Flash Memory Summit' to the 'Future of Memory and Storage' this year). Back at FMS 2022, the company had announced v3.0 of the CXL specifications. This was followed by CXL 3.1's introduction at Supercomputing 2023. Having started off as a host to device interconnect standard, it had slowly subsumed other competing standards such as OpenCAPI and Gen-Z. As a result, the specifications started to encompass a wide variety of use-cases by building a protocol on top of the the ubiquitous PCIe expansion bus. The CXL consortium comprises of heavyweights such as AMD and Intel, as well as a large number of startup companies attempting to play in different segments on the device side. At FMS 2024, CXL had a prime position in the booth demos of many vendors.
The migration of server platforms from DDR4 to DDR5, along with the rise of workloads demanding large RAM capacity (but not particularly sensitive to either memory bandwidth or latency), has opened up memory expansion modules as one of the first set of widely available CXL devices. Over the last couple of years, we have had product announcements from Samsung and Micron in this area.
At FMS 2024, SK hynix was showing off their DDR5-based CMM-DDR5 CXL memory module with a 128 GB capacity. The company was also detailing their associated Heterogeneous Memory Software Development Kit (HMSDK) - a set of libraries and tools at both the kernel and user levels aimed at increasing the ease of use of CXL memory. This is achieved in part by considering the memory pyramid / hierarchy and relocating the data between the server's main memory (DRAM) and the CXL device based on usage frequency.
The CMM-DDR5 CXL memory module comes in the SDFF form-factor (E3.S 2T) with a PCIe 3.0 x8 host interface. The internal memory is based on 1α technology DRAM, and the device promises DDR5-class bandwidth and latency within a single NUMA hop. As these memory modules are meant to be used in datacenters and enterprises, the firmware includes features for RAS (reliability, availability, and serviceability) along with secure boot and other management features.
SK hynix was also demonstrating Niagara 2.0 - a hardware solution (currently based on FPGAs) to enable memory pooling and sharing - i.e, connecting multiple CXL memories to allow different hosts (CPUs and GPUs) to optimally share their capacity. The previous version only allowed capacity sharing, but the latest version enables sharing of data also. SK hynix had presented these solutions at the CXL DevCon 2024 earlier this year, but some progress seems to have been made in finalizing the specifications of the CMM-DDR5 at FMS 2024.
Micron had unveiled the CZ120 CXL Memory Expansion Module last year based on the Microchip SMC 2000 series CXL memory controller. At FMS 2024, Micron and Microchip had a demonstration of the module on a Granite Rapids server.
Additional insights into the SMC 2000 controller were also provided.
The CXL memory controller also incorporates DRAM die failure handling, and Microchip also provides diagnostics and debug tools to analyze failed modules. The memory controller also supports ECC, which forms part of the enterprise... Storage
As LPCAMM2 adoption begins, the first retail memory modules are finally starting to hit the retail market, courtesy of Micron. The memory manufacturer has begun selling their LPDDR5X-based LPCAMM2 memory modules under their in-house Crucial brand, making them available on the latter's storefront. Timed to coincide with the release of Lenovo's ThinkPad P1 Gen 7 laptop – the first retail laptop designed to use the memory modules – this marks the de facto start of the eagerly-awaited modular LPDDR5X memory era.
Micron's Low Power Compression Attached Memory Module 2 (LPCAMM2) modules are available in capacities of 32 GB and 64 GB. These are dual-channel modules that feature a 128-bit wide interface, and are based around LPDDR5X memory running at data rates up to 7500 MT/s. This gives a single LPCAMM2 a peak bandwidth of 120 GB/s. Micron is not disclosing the latencies of its LPCAMM2 memory modules, but it says that high data transfer rates of LPDDR5X compensate for the extended timings.
Micron says that LPDDR5X memory offers significantly lower power consumption, with active power per 64-bit bus being 43-58% lower than DDR5 at the same speed, and standby power up to 80% lower. Meanwhile, similar to DDR5 modules, LPCAMM2 modules include a power management IC and voltage regulating circuitry, which provides module manufacturers additional opportunities to reduce power consumption of their products.

Source: Micron LPDDR5X LPCAMM2 Technical Brief
It's worth noting, however, that at least for the first generation of LPCAMM2 modules, system vendors will need to pick between modularity and performance. While soldered-down LPDDR5X memory is available at speeds up to 8533 MT/sec – and with 9600 MT/sec on the horizon – the fastest LPCAMM2 modules planned for this year by both Micron and rival Samsung will be running at 7500 MT/sec. So vendors will have to choose between the flexibility of offering modular LPDDR5X, or the higher bandwidth (and space savings) offered by soldering down their memory.
Micron, for its part, is projecting that 9600 MT/sec LPCAMM2 modules will be available by 2026. Though it's all but certain that faster memory will also be avaialble in the same timeframe.
Micron's Crucial LPDDR5X 32 GB module costs $174.99, whereas a 64 GB module costs $329.99.
MemoryA few years back, the Japanese government's New Energy and Industrial Technology Development Organization (NEDO ) allocated funding for the development of green datacenter technologies. With the aim to obtain up to 40% savings in overall power consumption, several Japanese companies have been developing an optical interface for their enterprise SSDs. And at this year's FMS, Kioxia had their optical interface on display.
For this demonstration, Kioxia took its existing CM7 enterprise SSD and created an optical interface for it. A PCIe card with on-board optics developed by Kyocera is installed in the server slot. An optical interface allows data transfer over long distances (it was 40m in the demo, but Kioxia promises lengths of up to 100m for the cable in the future). This allows the storage to be kept in a separate room with minimal cooling requirements compared to the rack with the CPUs and GPUs. Disaggregation of different server components will become an option as very high throughput interfaces such as PCIe 7.0 (with 128 GT/s rates) become available.
The demonstration of the optical SSD showed a slight loss in IOPS performance, but a significant advantage in the latency metric over the shipping enterprise SSD behind a copper network link. Obviously, there are advantages in wiring requirements and signal integrity maintenance with optical links.
Being a proof-of-concept demonstration, we do see the requirement for an industry-standard approach if this were to gain adoption among different datacenter vendors. The PCI-SIG optical workgroup will need to get its act together soon to create a standards-based approach to this problem.
StorageA few years back, the Japanese government's New Energy and Industrial Technology Development Organization (NEDO ) allocated funding for the development of green datacenter technologies. With the aim to obtain up to 40% savings in overall power consumption, several Japanese companies have been developing an optical interface for their enterprise SSDs. And at this year's FMS, Kioxia had their optical interface on display.
For this demonstration, Kioxia took its existing CM7 enterprise SSD and created an optical interface for it. A PCIe card with on-board optics developed by Kyocera is installed in the server slot. An optical interface allows data transfer over long distances (it was 40m in the demo, but Kioxia promises lengths of up to 100m for the cable in the future). This allows the storage to be kept in a separate room with minimal cooling requirements compared to the rack with the CPUs and GPUs. Disaggregation of different server components will become an option as very high throughput interfaces such as PCIe 7.0 (with 128 GT/s rates) become available.
The demonstration of the optical SSD showed a slight loss in IOPS performance, but a significant advantage in the latency metric over the shipping enterprise SSD behind a copper network link. Obviously, there are advantages in wiring requirements and signal integrity maintenance with optical links.
Being a proof-of-concept demonstration, we do see the requirement for an industry-standard approach if this were to gain adoption among different datacenter vendors. The PCI-SIG optical workgroup will need to get its act together soon to create a standards-based approach to this problem.
Storage
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