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 ESTSequential Read Performance
Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.
The retail SM2262EN drives offer the best QD1 sequential read performance, slightly faster than the earlier SM2262 drives and a clear improvement over the SM2262EN engineering sample we tested.
Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data. This test is run twice: once with the drive prepared by sequentially writing the test data, and again after the random write test has mixed things up, causing fragmentation inside the SSD that isn't visible to the OS. These two scores represent the two extremes of how the drive would perform under real-world usage, where wear leveling and modifications to some existing data will create some internal fragmentation that degrades performance, but usually not to the extent shown here.
On the longer sequential read test that includes some higher queue depths, the SM262EN drives provide top tier performance, but the Samsung 970 EVO Plus has a clear advantage when reading data that was not originally written sequentially.
Power Efficiency in MB/s/W | Average Power in W |
The power efficiency of the ADATA SX8200 Pro is second only to the Toshiba XG6 and slightly better than the Samsung 970 EVO Plus, though it and the other SM2262EN drives have subpar efficiency when reading fragmented data.
The retail SM2262EN drives hit their full sequential read speed at QD4 and hold steady through the rest of the test with the fastest read speeds we've measured from consumer SSDs. The Samsung 970 EVO Plus has about the same average at low queue depths thanks to better QD2 performance, but after that it takes until QD16 to reach its full speed.
Almost all of the NVMe SSDs that deliver sequential read speeds of greater than 2GB/s require more power than the ADATA SX8200 Pro, and of the few that are more efficient, none can come as close to the PCIe 3 x4 throughput limit.
Sequential Write Performance
Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.
The QD1 burst sequential write performance of the SM2262EN drives is much better than the earlier SM2262 drives, but the improvement isn't enough to beat the Phison E12-based Corsair MP510. The 1TB HP EX950 and ADATA SX8200 are faster than the 2TB model, which is also a bit slower than the 2TB SM2262EN engineering sample was.
Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.
On the longer sequential write test that includes some higher queue depths, the Samsung 970 EVO Plus is the fastest, and the SM2262EN drives are the only competitors that come close. The 2TB EX950 is again slightly slower than the 1TB drives.
Power Efficiency in MB/s/W | Average Power in W |
The 970 EVO Plus and Toshiba XG6 both deliver slightly better power efficiency on the sustained sequential write test than any of the SM2262EN drives. The ADATA SX8200 Pro continues to use less power than the HP EX950 of the same capacity, but the 2TB EX950 ends up with a comparable efficiency score to the ADATA due to being both slower and less power-hungry.
At QD2 the 1TB SM2262EN drives are very close to full sequential write performance, but the 2TB EX950 doesn't hit full speed until QD4. All three have steady performance through the higher queue depths, because this test doesn't come close to filling their large SLC caches.
Compared against the entire database of test results, the power efficiency of the ADATA SX8200 Pro doesn't really stand out; of the relatively few SSDs that provide similar levels of performance, several require less power.
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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.