Performance Comparisons – Sequential and Random
The SX8200 is not particularly spectacular when it comes to sequential writing, even with our burst method of writing that should be only hitting the SLC cache.
The story flips when we shift to sequential reads, with the SX8200 turning in extremely competitive results at the all-important QD 1-8 range. There's a decent area under that curve, separating it from the 970 EVO.
NAND SSDs are surprisingly fast at low QD random writes. This is for a few reasons. To explain better, let's review what happens when a typical NAND-flash SSD writes or reads:
- Writes: Host sends data to SSD. SSD receives data and acknowledges the IO. SSD then passes that data onto the flash for writing. All necessary metadata / FTL table updates take place.
- Reads: Host requests data from SSD. SSD controller looks up data location in FTL, addresses and reads data from the appropriate flash dies, and finally replies to the host with the data, completing the IO.
Picking out the SX8200 is tricky in this chart, as its curve identically matches the Intel SSD 760p (green line), which falls mid-pack. Not surprising as the 760p shares much of the same hardware.
For this chart, I've zoomed in a bit and shifted to a log scale so we can more clearly see the spread. Despite this, the grouping is still extremely close, and the easiest way to view this more clearly is to shift to our QD weighted results (next page).