Comparing Two 1TB NVMe Drives with Same NAND, Same Controller: XPG SX8200 Pro vs HP EX950
by Billy Tallis on February 6, 2019 11:30 AM ESTAnandTech Storage Bench - Heavy
Our Heavy storage benchmark is proportionally more write-heavy than The Destroyer, but much shorter overall. The total writes in the Heavy test aren't enough to fill the drive, so performance never drops down to steady state. This test is far more representative of a power user's day to day usage, and is heavily influenced by the drive's peak performance. The Heavy workload test details can be found here. This test is run twice, once on a freshly erased drive and once after filling the drive with sequential writes.
The Silicon Motion NVMe drives provide excellent overall performance when the Heavy test is run on an empty drive, but at the cost of much worse full-drive performance. This effect is not as strong for the 1TB models as for the 2TB HP EX950, which has also regressed overall from the performance of the pre-production firmware. The very slight gains the 1TB SM2262EN drives make over the HP EX920 in empty-drive performance do not come close to justifying the sacrifice in full-drive performance, especially since the SM2262 was already subpar in this respect.
The average and 99th percentile latency scores from the SM2262EN drives are unrivaled when the Heavy test is run on an empty drive, but when the drives are full the average latency scores regress to low-end NVMe levels and the 99th percentile latency scores end up comparable to mainstream SATA drives.
The best-case average read latency scores from the SM2262EN drives when the Heavy test is run on an empty drive are unchanged from the earlier SM2262 drives and remain among the best from any flash-based SSD. The empty-drive average write latencies are significantly faster than the older drives and are comparable to what Samsung's latest 970 EVO Plus provides. But as with the other metrics, performance on a full drive is not competitive with other high-end SSDs.
The 99th percentile read and write latency scores repeat the same story as above. Silicon Motion has optimized these drives for extremely good performance when they don't have much data to keep track of and can operate almost entirely from their SLC caches, but at great cost to worst-case behavior.
The ADATA SX8200 Pro again turns in much better power consumption scores than the HP EX950 or other SMI-based NVMe drives, but at its best it is still a bit more power-hungry than the WD Black and Toshiba's XG6. Due to the extreme performance drops when operating with a full drive, the SM2262EN drives all require much more energy to complete those test runs. That disparity in full vs empty energy efficiency is only matched by the QLC based drives like the Crucial P1 that also use a Silicon Motion controller and prioritize SLC cache performance.
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Mikewind Dale - Wednesday, February 6, 2019 - link
That drop in performance for a full drive in the Heavy - and even the Light!! - tests is worrying. They're right around the level of a SATA SSD.My question is, how full is full? If you fill the drive up 99%, is its performance closer to empty or full? With all my SSDs, I typically leave about 10% of the drive unallocated (unpartitioned). How would the drive perform in this state?
I would be interested in seeing results for a drive that is almost full, but not quite full. I imagine that most people don't use their drives up until the final MB is used. Still, if a cost-conscious person is trying to get their money's worth, they might use the drive until it's 90-something percent full. Until recently, I was using a 512 GB SATA SSD with a real capacity of 476.8 GB. I used it until I was using 420 GB, at which point I upgraded to a 2 TB drive. So I was using 88% of its capacity. To me, that seems like a reasonable usage to test - not quite full, but almost full.
Targon - Wednesday, February 6, 2019 - link
I would suspect that the reason for this might be thermal throttle issues. Throw a heat sink on there, and the performance downgrade might disappear. The versions with a pre-installed heatsink might be worth the money, depending on how much it would cost to buy a SSD heatsink at this point(I haven't looked).BillyONeal - Wednesday, February 6, 2019 - link
Seems more likely to be reduction in the size of the SLC cache -- see the the filling the drive tests where there are 3 distinct phases depending on how much space is actually in use.jabber - Thursday, February 7, 2019 - link
I must admit I still leave a few GB spare/unallocated on any SSD I install. 2GB on a 120GB, 4GB on a 240GB and 8GB on a 500GB. Old habits.reactor_au - Thursday, June 13, 2019 - link
I was wondering the same thing, how full can one get before performance drops off the cliff like in the benchmarks? Its a very import detail to omit!Luckz - Friday, November 29, 2019 - link
At 80% full it was really tragic in this review of the 256GB size https://pclab.pl/art79361-9.htmlMikewind Dale - Wednesday, February 6, 2019 - link
I also notice that these drives don't have an active power state less than 3.8W. That's unfortunate, because as Ganesh T S noted in his Anandtech review of the MyDigitalSSD M2X M.2 NVMe SSD Enclosure, that enclosure will only work with SSDs that have an active power state less than 3.8W.I think this is important because it determines whether you can continue to use the SSD as a portable drive after you upgrade later. If you replace your 2 TB with a 4 or 8 TB SSD someday in the future, it will be nice to know that you can repurpose your 2 TB as an external drive.
Also, it determines whether you can easily upgrade your SSD when all your M.2 slots are full. Whenever I upgrade a SATA boot drive, I typically use an external USB enclosure to clone the current SATA drive (still installed internally) to the new SATA drive (inside the enclosure). Then I can swap the two drives, and my computer will transparently use the new drive. With M.2, this is even more important because many motherboards have only two M.2 sockets. So if you have both M.2 sockets filled and try to upgrade one of the M.2 drives, you'll have a bit of a challenge. You could buy a PCIe-M.2 card and use that, but using an external USB enclosure is more convenient.
So I'd like to see more M.2 drives with a sub-3.8 W active power state. The Samsung 970 EVO Plus has a 3.4 W active state, so it passes this test.
MrSpadge - Wednesday, February 6, 2019 - link
I love ADATA's naming scheme! It's so easily memorable and has more X's than any other brand.eddieobscurant - Wednesday, February 6, 2019 - link
Nice review , as always although I disagree with your conclusion. Peak performance is what most people want.Billy Tallis - Wednesday, February 6, 2019 - link
My reviews are intended to advise consumers who are buying SSDs to increase their productivity, not people who are trying to set a high score on Crystal Disk Mark.People who care about real-world productivity rather than CDM scores should recognize that imperceptible improvements to peak performance are probably not worth the sacrifice of significant regressions in performance on niche heavy workloads. For a lot of users, both SM2262 and SM2262EN drives are fast enough. Beyond those lighter use cases, I think it will be more common to find the SM2262EN coming up short in a meaningful way than to find it providing a tangible performance advantage over SM2262.