4K Random Read/Write Speeds Are Very Slow

Drive was wiped using Secure-erase command on GParted software toolkit. Then Windows 7 Home Premium 64-bit installed afresh (not cloned or restored from a system image). Drive is plugged into SATA III add-on controller card (SYBA SD-PEX40054), a PCI-e x4 slot card with 2 lanes of bandwidth.

Ran CrystalDiskMark x64 version and AS-SSD benchmarks. Some of the read & write speeds look OK but i noticed the 4K random read/writes are particularly low - around 15.5MB/sec. read and 25MB/sec. write. Previously they were around 35MB/sec. read and 96MB/sec. write.

The rest of the benchmark results seem a little on the low side but not as bad as the 4K results.

Can anyone shed some light on how to improve these results? 

Hi Andrew, any updates on this for you yet? How “random” do you mean here?