Data Type Comparison And TLC Sequential Write Speed
Similar to the Phison S10-controlled drives, OCZ's Trion passes compressible and incompressible data through at different rates. Unlike SandForce-based SSDs that write incompressible data slower, Toshiba's controller reads compressible data at a higher speed.
When it comes to TLC NAND, we're mostly worried about sequential roll-off. This is a new test that we're running on products that use pSLC modes to hide the performance of slower flash technologies. Some MLC products are complemented with pSLC, but for the most part emulated SLC is used to mask the weaknesses of TLC.
Native TLC write performance is significantly lower than SLC or MLC. In the chart above, we write 64KB blocks to the full user LBA span of the Trion 100 480GB and observe performance right around 110 MB/s. There are mechanical hard drives that are faster.
The key to making TLC useful is to hide its native performance as much as possible. At the very start of the test, we see the Trion 100 480GB writing data at 427 MB/s. Sadly, that performance level is quite brief. Successfully masking the expected behavior of TLC memory means you need a large enough buffer to keep the drive from dropping to 110 MB/s transfers.