The Silicon Motion SM2262EN SSD Controller Preview: Good And Bad Amplified

Silicon Motion's second-generation NVMe SSD controllers have all but taken over the consumer NVMe SSD market. Drives like the HP EX920 and ADATA SX8200 currently offer great performance at prices that are far lower than what Samsung and Western Digital are charging for their flagship products. These Silicon Motion-based SSDs are using the SM2262 controller - the high-end member of SMI's current lineup - but they're almost as cheap as the entry-level NVMe drives that use low-end controllers with limited performance. Phison's second-generation high-end E12 controller still hasn't hit the shelves, so Silicon Motion has no serious competition for the SM2262.

But Silicon Motion isn't standing still. They've prepared an update to the SM2262 controller called the SM2262EN. This was first previewed at the same time that the SM2262 was announced, but Silicon Motion didn't provide much guidance on the timing. The SM2262 controller hit the market with the Intel SSD 760p in January, and the SM2262EN is almost ready for release. With the SM2262EN, Silicon Motion is promising substantial performance improvements that go well beyond what we usually see from firmware optimizations, though the hardware changes relative to the SM2262 are minimal. The updated controller should hit the market in time to compete against Phison E12 SSDs and the first wave of drives with 96-layer 3D NAND.

To assess the new SM2262EN controller solution, Silicon Motion has provided us with a 2TB reference design SSD with their latest firmware, a work in progress as Silicon Motion continues to optimize performance. This is a higher capacity drive than any of the SM2262 SSDs we've tested, and some performance improvement may be due simply to the capacity increase. However, even at 1TB we already have several NAND dies on each of the controller's 8 channels, so adding more dies shouldn't have a huge impact, especially not for sequential transfers.

SM2262 (left) and SM2262EN (right)

This 2TB configuration represents the maximum practical capacity when using 256Gb NAND dies, as it requires four packages with stacks of sixteen dies. The usable capacity is configured as about 2000 GB. The PCB layout is generally the same as for the SM2262 drives we've seen, with one DRAM package and two NAND packages on each side. This drive uses 2GB of Micron DDR4 DRAM, while all of the SM2262 retail drives we've seen use DDR3L.

The switch to DDR4 gives a slight improvement to voltage and latency, and a big boost to throughput—which is probably necessary to make the most of the EN controller variant. The use of DDR4 does add slightly to the cost of the drive, but not enough to prevent this change from carrying over into retail products. The DRAM update still leaves Silicon Motion a bit behind Samsung, which has moved its SSDs to LPDDR4 and reaped significant power savings.

For this review, the 2TB SM2262EN drive is compared against other recent NVMe SSDs, primarily high-end drives. The results from our engineering sample of the upcoming Phison E12 controller are also included, and these two new controller solutions will probably be responsible for the stiffest competition in the NVMe SSD market segment once they are both shipping in volume.

• Thanks to Intel for the Xeon E3 1240 v5 CPU
• Thanks to ASRock for the E3V5 Performance Gaming/OC
• Thanks to G.SKILL for the Ripjaws DDR4-2400 RAM
• Thanks to Corsair for the RM750 power supply, Carbide 200R case, and Hydro H60 CPU cooler
• Thanks to Quarch for the XLC Programmable Power Module and accessories
• Thanks to StarTech for providing a RK2236BKF 22U rack cabinet.