Feed: AnandTech
Feed Link: https://www.anandtech.com
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Title: Silicon Motion Demos Low-Power PCie 5.0 SSD Controller: SM2508

Date: Fri, 14 Jun 2024 09:00:00 EDT
Link: https://www.anandtech.com/show/21440/silicon-...

Rounding out our Computex 2024 SSD controller news, let's talk about the
final major controller vendor at the show: Silicon Motion. Silicon Motion has
been somewhat late to the PCIe Gen5 SSD party, as its rival Phison has been
offering their high-end PS5026-E26 controller for almost 18 months now. But
as Silicon Motion gets ready to make the transition to PCIe 5.0, the company
has a trump card up its sleeve: the SM2508 controller, an energy-efficient
high-end SSD controller that is intended for lower-power drives.

A PCIe Gen5 x4 controller, SMI's SM2508 boasts a very low active power
consumption of 3.5W. Which, installed in an M.2 SSD, is intended to allow
drive manufacturers to built 7 Watt (or lower) SSDs, according to the
company. The SM2508 is made on TSMC's N6 process technology, which is a 7nm-
class fabrication node with an optical shrink, which will make it one of the
(if not the) most advanced controllers on the market once it ships. The
relatively sophisticated node allows Silicon Motion to pack more cores and
more features into its controller while keeping its power consumption in
check - not to mention the chip size.

Silicon Motion NVMe Client SSD Controller Comparison SM2508 SM2264 SM2268XT2
SM2269XT Market Segment High-End Mainstream Manufacturing Process 6nm 12nm
12nm 12nm CPU Cores 4x Cortex R8 4x Cortex R8 2x Cortex R8 2x Cortex R8 Error
Correction 4K+ LDPC 4K LDPC 4K+ LDPC 4K LDPC DRAM DDR4, LPDDR4X DDR4, LPDDR4X
No No Host Interface PCIe 5.0 x4 PCIe 4.0 x4 PCIe 4.0 x4 PCIe 4.0 x4 NVMe
Version NVMe 2.0 NVMe 1.4 NVMe 2.0 NVMe 1.4 NAND Channels, Interface Speed 8
ch,
3600 MT/s 8 ch,
1600 MT/s 4 ch,
3600 MT/s 4 ch,
1600 MT/s Sequential Read 14.5 GB/s 7.5 GB/s 7.4 GB/s 5.1 GB/s Sequential
Write 14 GB/s 7 GB/s 6.7 GB/s 4.8 GB/s 4KB Random Read IOPS 2500k 1300k 1200k
900k 4KB Random Write IOPS 2500k 1200k 1200k 900k

Under the hood, the front-end of the SM2508 SSD controller is based around
four Arm Cortex-R8 cores, which will make it a notably powerful controller
(Phison's E26, for reference, is two Arm Cortex R5 cores with an
accelerator). This controller is meant to be used with DRAM, as well, and
will support both DDR4 and LPDDR4.

The back-end of the chip offers eight NAND channels with 32 CE targets,
supporting interface speeds up to 3600 MT/s. Altogether, SMI says that the
controller can hit sequential read speeds of up to 14.5GB/sec and write
speeds of up to 14 GB/s, while 4K random read and write performance will
reach up to 2.5 million IOPS. And SMI's demo drive at Computex did even
better than that, achieving a 14.9GB/sec read speed under CrystalDiskMark.

Silicon Motion and its partners are currently finalizing the firmware for the
SM2508 and qualifying it with various manufacturers' TLC NAND. The chip also
supports QLC NAND, though we'd be surprised to see anyone pair such a
powerful controller with slower NAND so soon.

At Computex, Silicon Motion itself demonstrated an SM2508 drive in action at
its booth. Various drive manufacturers also had SM2508-based drives on the
floor as well, though only as static samples.

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