Latency and 4K Random
The fact that we cannot entirely saturate the 9207-8i leaves us with few parameters that we can test to compare the generational differences between using the 9207-8i with PCIe 3.0 and the 9211-8i with the PCIe 2.0 interface. Typical tests such as our Iometer server emulations will fall short, only showing the limitations of the SSDs themselves.
This leaves us with testing the latency of the HBAs and the sequential read speed with the Crucial M4s. Then we will move onto testing the maximum IOPS with the SanDisk ESS Lightning's.
The 4K latency test reveals that the latency between the two HBAs is very close, with the values listed above the line being the 9207-8i's latency. There is not any significantly appreciable difference between the two.
The 4K random speed, tested with the Crucial M4s, scales nicely with both controllers, yet falls far short of being able to reach the controllers limits. The 9207-8i has a slightly better latency, which leads to a small difference at the upper end of the chart.
The write results are closely aligned as well, with the 9207-8i pulling slightly ahead. This may be due to the variability of performance that can be associated with SSDs, since both are not near the IOPS ceiling for each respective controller. There simply are not SSDs available on the market currently that can provide the amount of write IOPS sufficient to saturate the 9207-8i with only eight devices.