Silicon Motion SM2256 SSD Controller Preview: TLC for Everyone

Random Read Performance

For full details of how we conduct our Iometer tests, please refer to this article.

Random read performance has never been Silicon Motion's biggest strength and it actually slightly decreases with the new SM2256 controller, although that's most likely due to the slower TLC NAND. 

Power also goes up quite significantly, but compared to other drive it's still relatively low -- just not SM2246EN low.

SMI 2256 Reference Design 500GBCorsair Neutron XT 480GBCrucial BX100 120GBCrucial BX100 250GBCrucial BX100 500GBCrucial BX100 1TBCrucial MX100 512GBCrucial MX200 250GBCrucial MX200 500GBCrucial MX200 1TBOCZ Vector 180 240GBOCZ Vector 180 480GBOCZ Vector 180 960GBSamsung 850 EVO M.2 120GBSamsung 850 EVO mSATA 250GBSamsung 850 EVO M.2 500GBSamsung 850 EVO mSATA 1TBSamsung 850 EVO 1TBSamsung SSD 850 Pro 512GBSanDisk Extreme Pro 480GBSanDisk Ultra II 240GB

Queue depth scaling behavior seems to be similar to the SM2246EN, although at a higher power consumption. The scaling could be a little more aggressive because especially the QD4 and QD8 scores can't match the competition. 

Random Write Performance

Random write performance isn't too good as the SMI 2256 turns out to be the slowest of the bunch. I wonder how big of a difference another manufacturer's TLC NAND would make, but we should find that out once the retail drives ship in the next couple of months. 

Power efficiency is pretty poor given that performance is low, but power consumption is average. 

SMI 2256 Reference Design 500GBCorsair Neutron XT 480GBCrucial BX100 120GBCrucial BX100 250GBCrucial BX100 500GBCrucial BX100 1TBCrucial MX100 512GBCrucial MX200 250GBCrucial MX200 500GBCrucial MX200 1TBOCZ Vector 180 240GBOCZ Vector 180 480GBOCZ Vector 180 960GBSamsung 850 EVO M.2 120GBSamsung 850 EVO mSATA 250GBSamsung 850 EVO M.2 500GBSamsung 850 EVO mSATA 1TBSamsung 850 EVO 1TBSamsung SSD 850 Pro 512GBSanDisk Extreme Pro 480GBSanDisk Ultra II 240GB

It's obvious that TLC NAND limits the performance because there's practically almost no scaling at all with the queue depth. The good news is that low QD performance is pretty decent -- it's the high QD operations that suffer the most from TLC NAND, but those are very rare in typical client workloads.