<data:blog.pageName/>

Kioxia Details BiCS 8 NAND at FMS 2024: 218 Layers With Superior Scaling
Kioxia'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.

Storage

March 12, 2025

Kioxia Details BiCS 8 NAND at FMS 2024: 218 Layers With Superior Scaling
Kioxia'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.

Storage

March 12, 2025

Kioxia's High-Performance 3D QLC NAND Enables High-End High-Capacity SSDs <p align="center"><a href="https://www.anandtech.com/show/21464/kioxias-highperformance-3d-qlc-nand-enables-highend-highcapacity-ssds"><img src="https://images.anandtech.com/doci/21464/kioxia-nand-678_575px.png" alt="" /></a></p><p><p>This week, Kioxia introduced its new 3D QLC NAND devices aimed at high-performance, high-capacity drives that could redefine what we typically expect from QLC-based SSDs. The components are 1 Tb and 2 Tb 3D QLC NAND ICs with a 3600 MT/s interface speed that could enable M.2-2230 SSDs with a 4 TB capacity and decent performance.</p>

<p>Kioxia's 1 Tb (128 MB) and 2 Tb (256 TB) 3D QLC NAND devices are made on the company's BICS 8 process technology and feature 238 active layers as well as CMOS directly Bonded to Array (CBA) design, which implies that CMOS (including interface and buffers circuitry) is built on a specialized node and bonded to the memory array. Such a manufacturing process enabled Kioxia (and its manufacturing partner Western Digital) to achieve a particularly high interface speed of 3600 MT/s.</p>

<p>In addition to being one of the industry's first 2 Tb QLC NAND devices, the component features a 70% higher write power efficiency compared to Kioxia's BICS 5 3D QLC NAND devices, which is a bit vague statement as the new ICs have higher capacity and performance in general. This feature will be valuable for data centre applications, though I do not expect someone to use 3D QLC memory for write-intensive applications in general. Yet, these devices will be just what the doctor ordered for AI: read-intensive, content distribution, and backup storage.</p>

<p>It is interesting to note that Kioxia's 1 Tb 3D QLC NAND, optimized for performance, has a 30% faster sequential write performance and a 15% lower read latency than the 2 Tb 3D QLC component. These qualities (alongside a 3600 MT/s interface) promise to make Kioxia's 1 Tb 3D QLC competitive even for higher-end PCIe Gen5 x4 SSDs, which currently exclusively use 3D TLC memory.</p>

<p>The remarkable storage density of Kioxia's 2Tb 3D QLC NAND devices will allow customers to create high-capacity SSDs in compact form factors. For instance, a 16-Hi stacked package (measuring 11.5 mm × 13.5 mm × 1.5 mm) can be used to build a 4TB M.2-2230 drive or a 16TB M.2-2280 drive. Even a single 16-Hi package could be enough to build a particularly fast client SSD.</p>

<p>Kioxia is now sampling its 2 Tb 3D QLC NAND BiCS 8 memory with customers, such as Pure Storage.</p>

<p>"<em>We have a long-standing relationship with Kioxia and are delighted to incorporate their eighth-generation BiCS Flash 2Tb QLC flash memory products to enhance the performance and efficiency of our all-flash storage solutions,</em>" said Charles Giancarlo, CEO of Pure Storage. "<em>Pure's unified all-flash data storage platform is able to meet the demanding needs of artificial intelligence as well as the aggressive costs of backup storage. Backed by Kioxia technology, Pure Storage will continue to offer unmatched performance, power efficiency, and reliability, delivering exceptional value to our customers.</em>"</p>

<p>"<em>We are pleased to be shipping samples of our new 2Tb QLC with the new eighth-generation BiCS flash technology,</em>" said Hideshi Miyajima, CTO of Kioxia. "<em>With its industry-leading high bit density, high speed data transfer, and superior power efficiency, the 2Tb QLC product will offer new value for rapidly emerging AI applications and large storage applications demanding power and space savings.</em>"</p>

<p>There is no word on when the 1 Tb 3D QLC BiCS 8 memory will be sampled or released to the market.</p>
</p> SSDs

Kioxia's High-Performance 3D QLC NAND Enables High-End High-Capacity SSDs
This week, Kioxia introduced its new 3D QLC NAND devices aimed at high-performance, high-capacity drives that could redefine what we typically expect from QLC-based SSDs. The components are 1 Tb and 2 Tb 3D QLC NAND ICs with a 3600 MT/s interface speed that could enable M.2-2230 SSDs with a 4 TB capacity and decent performance.

Kioxia's 1 Tb (128 MB) and 2 Tb (256 TB) 3D QLC NAND devices are made on the company's BICS 8 process technology and feature 238 active layers as well as CMOS directly Bonded to Array (CBA) design, which implies that CMOS (including interface and buffers circuitry) is built on a specialized node and bonded to the memory array. Such a manufacturing process enabled Kioxia (and its manufacturing partner Western Digital) to achieve a particularly high interface speed of 3600 MT/s.

In addition to being one of the industry's first 2 Tb QLC NAND devices, the component features a 70% higher write power efficiency compared to Kioxia's BICS 5 3D QLC NAND devices, which is a bit vague statement as the new ICs have higher capacity and performance in general. This feature will be valuable for data centre applications, though I do not expect someone to use 3D QLC memory for write-intensive applications in general. Yet, these devices will be just what the doctor ordered for AI: read-intensive, content distribution, and backup storage.

It is interesting to note that Kioxia's 1 Tb 3D QLC NAND, optimized for performance, has a 30% faster sequential write performance and a 15% lower read latency than the 2 Tb 3D QLC component. These qualities (alongside a 3600 MT/s interface) promise to make Kioxia's 1 Tb 3D QLC competitive even for higher-end PCIe Gen5 x4 SSDs, which currently exclusively use 3D TLC memory.

The remarkable storage density of Kioxia's 2Tb 3D QLC NAND devices will allow customers to create high-capacity SSDs in compact form factors. For instance, a 16-Hi stacked package (measuring 11.5 mm × 13.5 mm × 1.5 mm) can be used to build a 4TB M.2-2230 drive or a 16TB M.2-2280 drive. Even a single 16-Hi package could be enough to build a particularly fast client SSD.

Kioxia is now sampling its 2 Tb 3D QLC NAND BiCS 8 memory with customers, such as Pure Storage.

"We have a long-standing relationship with Kioxia and are delighted to incorporate their eighth-generation BiCS Flash 2Tb QLC flash memory products to enhance the performance and efficiency of our all-flash storage solutions," said Charles Giancarlo, CEO of Pure Storage. "Pure's unified all-flash data storage platform is able to meet the demanding needs of artificial intelligence as well as the aggressive costs of backup storage. Backed by Kioxia technology, Pure Storage will continue to offer unmatched performance, power efficiency, and reliability, delivering exceptional value to our customers."

"We are pleased to be shipping samples of our new 2Tb QLC with the new eighth-generation BiCS flash technology," said Hideshi Miyajima, CTO of Kioxia. "With its industry-leading high bit density, high speed data transfer, and superior power efficiency, the 2Tb QLC product will offer new value for rapidly emerging AI applications and large storage applications demanding power and space savings."

There is no word on when the 1 Tb 3D QLC BiCS 8 memory will be sampled or released to the market.

SSDs

July 28, 2024

Realtek Outlines SSD Controller Roadmap: High-End PCIe 5.0 x4 Platform in the Works <p align="center"><a href="https://www.anandtech.com/show/21441/realtek-unwraps-ssd-controller-roadmap-highend-pcie-50-x4-platform-in-the-works"><img src="https://images.anandtech.com/doci/21441/realtek-ssd-678_575px.jpg" alt="" /></a></p><p><p>While Realtek is best known in the enthusiast space for for its peripheral controllers such as audio codecs and network controllers, the company also has a small-but-respectable SSD controller business that tends to fly under the radar due to its focus on entry-level and mainstream drives. But Realtek's stature in the SSD space is on the rise, as the company is not only planning new PCIe Gen5 SSD controllers, but also their first high-end, DRAM-equipped SSD controller.</p>

<p>For this year's Computex trade show, Realtek laid out a new SSD controller roadmap that calls for the company to release a trio of new SSD controllers over the next couple of years. First up is a new four-channel entry-level PCIe 4.0 controller, the RTS5776DL, which will be joined a bit later by a PCIe 5.0 variant, the RTS5781DL. But most interesting on Realtek's new roadmap is the final chip being planned: the eight-channel, DRAM-equipped RTS5782, which would be the company's first high-end SSD controller, capable of hitting sequential read rates as high as 14GB/second.</p>

<table align="center" border="1" cellpadding="1" cellspacing="1" width="95%">
<tbody>
<tr class="tgrey">
<td align="center" colspan="10">Realtek NVMe SSD Controller Comparison</td>
</tr>
<tr class="tlblue">
<td style="width: 130px;"> </td>
<td style="width: 90px;">RTS5782</td>
<td style="width: 90px;">RTS5781DL</td>
<td style="width: 90px;">RTS5776DL</td>
<td style="width: 90px;">RTS5772DL</td>
<td style="width: 90px;">RTS5766DL</td>
</tr>
<tr>
<td class="tlgrey">Market Segment</td>
<td style="text-align: center;">High-End</td>
<td colspan="3" style="text-align: center;">Mainstream</td>
<td rowspan="1" style="text-align: center;">Entry-Level</td>
</tr>
<tr>
<td class="tlgrey">Error Correction</td>
<td colspan="3" style="text-align: center;">4K LDPC</td>
<td colspan="2" style="text-align: center;">2K LDPC</td>
</tr>
<tr>
<td class="tlgrey" rowspan="1">DRAM</td>
<td rowspan="1" style="text-align: center;">DDR4, LPDDR4(X)</td>
<td rowspan="1" style="text-align: center;">No</td>
<td rowspan="1" style="text-align: center;">No</td>
<td rowspan="1" style="text-align: center;">No</td>
<td rowspan="1" style="text-align: center;">No</td>
</tr>
<tr>
<td class="tlgrey">Host Interface</td>
<td style="text-align: center;">PCIe 5.0 x4</td>
<td style="text-align: center;">PCIe 5.0 x4</td>
<td style="text-align: center;">PCIe 4.0 x4</td>
<td rowspan="1" style="text-align: center;">PCIe 4.0 x4</td>
<td rowspan="1" style="text-align: center;">PCIe 3.0 x4</td>
</tr>
<tr>
<td class="tlgrey">NVMe Version</td>
<td style="text-align: center;">NVMe 2.0</td>
<td style="text-align: center;">NVMe 2.0</td>
<td style="text-align: center;">NVMe 2.0</td>
<td style="text-align: center;">NVMe 1.4</td>
<td style="text-align: center;">NVMe 1.4</td>
</tr>
<tr>
<td class="tlgrey" rowspan="1">NAND Channels, Interface Speed</td>
<td rowspan="1" style="text-align: center;">8 ch,<br />
3600 MT/s</td>
<td rowspan="1" style="text-align: center;">4 ch,<br />
3600 MT/s</td>
<td rowspan="1" style="text-align: center;">4 ch,<br />
3600 MT/s</td>
<td rowspan="1" style="text-align: center;">8 ch,<br />
1600 MT/s</td>
<td rowspan="1" style="text-align: center;">4 ch,<br />
1200 MT/s</td>
</tr>
<tr>
<td class="tlgrey">Sequential Read</td>
<td style="text-align: center;">14 GB/s</td>
<td style="text-align: center;">10 GB/s</td>
<td style="text-align: center;">7.4 GB/s</td>
<td style="text-align: center;">6 GB/s</td>
<td style="text-align: center;">3.2 GB/s</td>
</tr>
<tr>
<td class="tlgrey">Sequential Write</td>
<td style="text-align: center;">12 GB/s</td>
<td style="text-align: center;">10 GB/s</td>
<td style="text-align: center;">7.4 GB/s</td>
<td style="text-align: center;">6 GB/s</td>
<td style="text-align: center;">2.2 GB/s</td>
</tr>
<tr>
<td class="tlgrey">4KB Random Read IOPS</td>
<td style="text-align: center;">2500k</td>
<td style="text-align: center;">1400k</td>
<td style="text-align: center;">1200k</td>
<td style="text-align: center;">-</td>
<td style="text-align: center;">-</td>
</tr>
<tr>
<td class="tlgrey">4KB Random Write IOPS</td>
<td style="text-align: center;">2500k</td>
<td style="text-align: center;">1400k</td>
<td style="text-align: center;">1200k</td>
<td style="text-align: center;">-</td>
<td style="text-align: center;">-</td>
</tr>
</tbody>
</table>

<p>Diving a bit deeper into Realtek's roadmap, the RTS5776DL is traditional DRAM-less PCIe Gen4 x4 controller with four NAND chann... SSDs

Realtek Outlines SSD Controller Roadmap: High-End PCIe 5.0 x4 Platform in the Works
While Realtek is best known in the enthusiast space for for its peripheral controllers such as audio codecs and network controllers, the company also has a small-but-respectable SSD controller business that tends to fly under the radar due to its focus on entry-level and mainstream drives. But Realtek's stature in the SSD space is on the rise, as the company is not only planning new PCIe Gen5 SSD controllers, but also their first high-end, DRAM-equipped SSD controller.

For this year's Computex trade show, Realtek laid out a new SSD controller roadmap that calls for the company to release a trio of new SSD controllers over the next couple of years. First up is a new four-channel entry-level PCIe 4.0 controller, the RTS5776DL, which will be joined a bit later by a PCIe 5.0 variant, the RTS5781DL. But most interesting on Realtek's new roadmap is the final chip being planned: the eight-channel, DRAM-equipped RTS5782, which would be the company's first high-end SSD controller, capable of hitting sequential read rates as high as 14GB/second.

Realtek NVMe SSD Controller Comparison

RTS5782 RTS5781DL RTS5776DL RTS5772DL RTS5766DL

Market Segment High-End Mainstream Entry-Level

Error Correction 4K LDPC 2K LDPC

DRAM DDR4, LPDDR4(X) No No No No

Host Interface PCIe 5.0 x4 PCIe 5.0 x4 PCIe 4.0 x4 PCIe 4.0 x4 PCIe 3.0 x4

NVMe Version NVMe 2.0 NVMe 2.0 NVMe 2.0 NVMe 1.4 NVMe 1.4

NAND Channels, Interface Speed 8 ch,
3600 MT/s 4 ch,
3600 MT/s 4 ch,
3600 MT/s 8 ch,
1600 MT/s 4 ch,
1200 MT/s

Sequential Read 14 GB/s 10 GB/s 7.4 GB/s 6 GB/s 3.2 GB/s

Sequential Write 12 GB/s 10 GB/s 7.4 GB/s 6 GB/s 2.2 GB/s

4KB Random Read IOPS 2500k 1400k 1200k - -

4KB Random Write IOPS 2500k 1400k 1200k - -

Diving a bit deeper into Realtek's roadmap, the RTS5776DL is traditional DRAM-less PCIe Gen4 x4 controller with four NAND chann... SSDs

July 10, 2024

$ASRock Launches Passively Cooled Radeon RX 7900 XTX & XT Cards for Servers <a href="https://www.anandtech.com/show/21491/asrock-launches-passively-cooled-radeon-rx-7900-xtx-and-xt"><img src="https://images.anandtech.com/doci/21491/ASRock-Launches-AMD-Radeon--RX-790-0-Passive-Series-Graphics-Cards-678_575px.jpg" alt="" /></a>As sales of GPU-based AI accelerators remain as strong as ever, the immense demand for these cards has led to some server builders going off the beaten path in order to get the hardware they want at a lower price. While both NVIDIA and AMD offer official card configurations for servers, the correspondingly high price of these cards makes them a significant financial outlay that some customers either can't afford, or don't want to pay. Instead, these groups have been turning to buying up consumer graphics cards, which although they come with additional limitations, are also a fraction of the cost of a "proper" server card. And this week, ASRock has removed another one of those limitations for would-be AMD Radeon users, with the introduction of a set of compact, passively-cooled Radeon RX 7900 XTX and RX 7900 XT video cards that are designed to go in servers. Without any doubts, ASRock's <a href="https://www.asrock.com/Graphics-Card/AMD/Radeon%20RX%207900%20XTX%20Passive%2024GB/">AMD Radeon RX 7900 XTX Passive 24GB</a> and <a href="https://www.asrock.com/Graphics-Card/AMD/Radeon%20RX%207900%20XT%20Passive%2020GB/">AMD Radeon RX 7900 XT Passive 20GB</a> AIBs are indeed graphics cards with four display outputs and based on the Navi 31 graphics processor (with 6144 and 5376 stream processors, respectively), so they can output graphics and work both with games and professional applications. And with TGPs of 355W and 315W respectively, these cards aren't underclocked in any way compared to traditional desktop cards. However, unlike a typical desktop card, the cooler on these cards is a dual-slot heatsink without any kind of fan attached, which is meant to be used with high-airflow forced-air cooling. <a href="https://www.anandtech.com/show/21491/asrock-launches-passively-cooled-radeon-rx-7900-xtx-and-xt"><img alt="" src="https://images.anandtech.com/doci/21491/ASRock-Launches-AMD-Radeon--RX-790-0-Passive-1_575px.jpg" /></a> All-told, ASRock's passive cooler is pretty capable, as well; it's not just a simple aluminum heatsink. Beneath the fins, ASRock has gone with a vapor chamber and multiple heat pipes to distribute heat to the rest of the sink. Even with forced-air cooling in racked servers, the heatsink itself still needs to be efficient to keep a 300W+ card cool with only a dual-slot cooler – and especially so when upwards of four of these cards are installed side-by-side with each other. To make the boards even more server friendly, these cards are equipped with a 12V-2×6 power connector, a first for the Radeon RX 7900 series, simplifying installation by reducing cable clutter. <a href="https://www.anandtech.com/show/21491/asrock-launches-passively-cooled-radeon-rx-7900-xtx-and-xt"><img alt="" src="https://images.anandtech.com/doci/21491/ASRock-Launches-AMD-Radeon--RX-790-0-Passive-2_575px.jpg" /></a> Driving the demand for these cards in particular is their memory configuration. With 24GB for the 7900 XTX and 20GB for the 7900 XT is half as much (or less) memory than can be found on AMD and NVIDIA's high-end professional and server cards, AMD is the only vendor offering consumer cards with this much memory for less than $1000. So for a memory-intensive AI inference cluster built on a low budget, the cheapest 24GB card available starts looking like a tantalizing option. Otherwise, ASRock's Radeon RX 7900 Passive cards distinguish themselves from AMD's formal professional and server cards by what they're not capable of doing: namely, remote professional graphics or other applications that need things like GPU partitioning. These parts look to be aimed at one application only, artificial intelligence, and are meant to process huge amounts of data. For this purpose, their passive coolers will do the job and the lack of ProViz or VDI-oriented drives ensure that AMD will leave these lucrative markets for itself. GPUs$