Performance Comparisons – Sequential and Random

Both capacities of the RC100 do fairly well here. Note that we have included some SATA parts in this comparison since the cost/GB is theoretically comparable (more on that at the end of the article).

Good performance on sequential reads as well.

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.

Things don't fare so well for the RC100's in random writes. Despite our random write workload being bursty in nature as to give caching SSDs the best chance at actually using their cache, both RC100's are at the bottom of these plots – even well below the SATA SSDs that were included for comparison.

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).

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