ADATA XPG SX900 (128GB) Review: Maximizing SandForce Capacityby Kristian Vättö on June 8, 2012 1:25 AM EST
Performance Over Time and TRIM
Usually we use HD Tach to test TRIM performance but since SandForce drives do real-time compression, using HD Tach and compressible data would not give us a good idea of worst case performance. Instead, I filled the drive with incompressible data and proceeded to hammer it with incompressible 4KB random writes (QD32) for 60 minutes. Then I ran AS-SSD which uses incompressible data as well to see how the SX900 performs in worst case state. Finally I TRIMed the drive and ran AS-SSD again to test whether TRIM recovers the performance.
|ADATA XPG SX900 - Resiliency - AS SSD Sequential Write Speed - 6Gbps|
|Clean||After Torture||After TRIM|
|ADATA XPG SX900 128GB||175.4MB/s||35.4MB/s||146.8MB/s|
|ADATA S511 120GB||160.8MB/s||96.4MB/s||98.8MB/s|
There is quite a big difference between the two ADATA drives when it comes to TRIM and post-torture performance. The S511 performs much better after torture but TRIM is not very effective. The SX900, on the other hand, is the complete opposite. Its performance is poor after torture but a single TRIM pass will almost restore the performance back to clean state, as after TRIM the performance is back to 84% of clean performance. The S511 is definitely an odd case because for example OCZ Vertex 3 behaves similarly with the SX900. However, the important part is that TRIM is able to restore the performance, which is what matters. Firmware is the apparent culprit once again, and it's unfortunate that the S511 hasn't been updated in quite some time.
Again, what I would like to emphasize that our torture scenario is an extreme case. In the real world, it's impossible to create a such scenario if you are using the SSD as a boot drive. That's because you will at least have Windows or some other easily compressible OS on the drive. Even if the drive was used as a storage drive, it's still fairly unlikely that you would fill it with incompressible data only, and what's more it is highly unlikely that a majority of your writes would be random in nature.