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 ESTMixed Random Performance
Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.
The ADATA SX8200 Pro and HP EX950 provide top-tier performance on our mixed random I/O test, just shy of the Samsung 970 EVO Plus. The 2TB EX950 has almost identical overall performance to the 1TB models.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The power efficiency of the ADATA SX8200 Pro isn't quite as good as the Toshiba XG6 or WD Black SN750, but it's well ahead of the rest of the flash-based SSDs, including the HP EX950.
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Compared to their predecessors and most of the competition, the SX8200 Pro and EX950 offer better performance during the read-heavy half of the test. The 970 EVO Plus pulls ahead during the write-heavy half of the test, which is generally faster anyways since write operations can be cached and combined. The Toshiba XG6 and WD Black SN750 that are more efficient than the SX8200 Pro are slower during every phase of the test except for the final segment with pure writes.
Mixed Sequential Performance
Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.
The SM2262EN drives provide great performance on the mixed sequential I/O test, but the Samsung 970 EVO Plus maintains a clear lead, and the 2TB HP EX950 is back to being slower than the 1TB models.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The 1TB ADATA SX8200 Pro just barely provides top-tier power efficiency on the mixed sequential I/O test, but the handful of drives that score better include most of the important competition: the latest from Samsung, WD, Toshiba and Phison.
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The 2TB HP EX950 is slower than the 1TB model throughout the test, except for the pure read and write segments at either end. The 1TB SX8200 Pro and EX950 outperform their predecessors by an increasingly large margin as the workload becomes more write-heavy. The Samsung 970 EVO Plus that turns in the fastest overall performance runs up the score during the read-heavy half of the test but is no faster than the SM2262EN drives during the write-heavy half.
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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.