The first reviews of Silicon Motion's new PCIe 5.0 NVMe SSD controller, the SM2508 are starting to appear online, and the good news is that the controller is as power efficient as promised by the company. Tom's hardware has put up their review of a reference design M.2 SSD from Silicon Motion and in their testing, equipped with 1 TB of Kioxia's 162-layer BiCS6 TLC NAND. It easily bests the competition when it comes to power efficiency. In their file copy test, it draws nearly two watts less than its nearest competitor and as much as three watts less than the most power hungry drive. It's still using about one watt more than the best PCIe 4.0 drives, but it goes to show that the production nodes matters, as the SM2508 is produced on a 6 nm node, compared to 12 nm for Phison's E26.

We should point out that the peak power consumption did go over nine watts, but only one of the Phison E26 drives managed to stay below 10 watts here. The most power hungry PCIe 5.0 SSD controller in the test, the InnoGrit IG5666 peaks at nearly 14 watts for comparison. Idle power consumption of the SM2508 is also very good, still drawing more than the PCIe 4.0 drives it was tested against, but far less than any of the other PCIe 5.0 drives. What about performance you ask? The reference drive places itself ahead of all the Phison E26 drives when it comes to sequential file transfers, regardless if it's to or from the drive. Random read IOPS also places right at the top, but it's somewhat behind when it comes to random writes, without being a slow drive by any means. Overall we're looking at a very promising new SSD controller from Silicon Motion with the SM2508 and TPU has also received a sample that is currently undergoing testing, so expect a review here soon.

Silicon Motion Technology Corporation, a global leader in designing and marketing NAND flash controllers for solid-state storage devices, today announced SM2508, the best power efficiency PCIe Gen 5 NVMe 2.0 client SSD controller for AI PCs and gaming consoles. It's the world's first PCIe Gen 5 client SSD controller using TSMC's 6 nm EUV process, offering a 50% reduction in power consumption compared to competitive offerings in the 12 nm process. With less than 7 W power consumption for the entire SSD, it delivers 1.7x better power efficiency than PCIe Gen 4 SSDs and up to 70% better than current competitive PCIe Gen 5 offerings on the market. Silicon Motion will be showcasing its SM2508 based SSD design and other innovations during the Future of Memory and Storage event from Aug. 6 to 8 at booth #315:

Silicon Motion's SM2508 is a superior-performance, low-power PCIe Gen 5 x4 NVMe 2.0 SSD controller designed for AI-capable PC notebooks. It supports eight NAND channels with up to 3,600 MT/s per channel, delivering sequential performance speeds of up to 14.5 GB/s and 13.6 GB/s and random performance speeds of up to 2.5M IOPS, providing up to 2x higher performance than PCIe Gen 4 products. The SM2508 maximizes PCIe Gen 5 performance with an impressive power consumption of approximately 3 W. It features Silicon Motion's proprietary 8th-generation NANDXtend technology, which includes an on-disk training algorithm designed to reduce ECC timing. This enhancement boosts performance and maximizes power efficiency while ensuring compatibility with the latest 3D TLC/QLC NAND technologies, enabling higher data density and meeting the evolving demands of next-generation AI PCs.

Silicon Motion's SM2508 was first revealed in August last year at the Flash Memory Summit 2023, but after that things went pretty quiet. However, the company was demoing the SM2508 up and running at Computex this past week and it's set to edge out Phison's E26 Max14um in the battle of fastest NVMe SSD controller. We're not talking about any massive gains here, but the reference drive from Silicon Motion was shown running CrystalDiskMark 8.0.4 at the show and if we do a rough comparison to a Phison E26 Max14um, the SM2508 beats Phison by about 800 MB/s in sequential read performance and 500 MB/s in sequential write performance.

This might not seem like a whole lot, but the SM2508 is built on TSMC's N6 node which results in a 3.5 Watt peak power consumption, or 7 Watts for the entire SSD at load. A typical Phison E26 based SSD draws in excess of 11 Watts of power at full load, which is a big difference in a mobile device. This should obviously also lead to lower thermals and we should finally see PCIe 5.0 drives that don't need massive heatsinks or active cooling. In fact, 7 Watts power draw is very similar to Phison's E18 PCIe 4.0 based SSDs. Silicon Motion is still working on fine tuning the firmware for the SM2508, so performance might yet improve to reach the promised 14 GB/s write performance. Currently the random performance is also looking a bit on the weak side compared to Phison. According to Tom's hardware, we should see the first drives with the Silicon Motion SM2508 appear in the market sometime in Q4 this year.

It appears that Silicon Motion is ready to start competing with Phison in the PCIe 5.0 NVMe SSD controller market, as the company has shown a new controller at the Flash Memory Summit 2023 which should give Phison a run for its money. The SM2508 as the controller is called is set to be the most power efficient PCIe 5.0 NVMe controller to date, with a power consumption of 3.5 W, which is in line with most PCIe 4.0 SSD controllers. This still means that a decent heatsink will be needed, but not active cooling or massive heatsinks that we've seen on the current crop of PCIe 5.0 drives based on Phison's E26 controller.

Silicon Motion also appears to have the Phison E26 beat, in terms of performance, as the SM2508 promises to deliver sequential read and write speeds of up to 14 GB/s. Random performance is rated at 2.5 million IOPS read and 2.4 million IOPS write. To get the most out of the SM2508 2400 MT/s or faster NAND flash is going to be needed to deliver the claimed performance figures though, but according to Anandtech, the SM2508 is future proofed by supporting NAND flash speeds of up to 3600 MT/s, so we might see faster drives based on the controller once faster NAND appears, such as SK Hynix new 321-layer NAND, which is scheduled for a 2025 introduction. The SM2508 on the other hand is said to be launching at the end of this year or early 2024.