I have SuperMicro computer with LSI 9240-8i card and eight WD40EFRX drives.
There is RAID 5 volume with 64KB strip size over all eight drives.
I have current firmware, current driver, operating system is Windows Server 2012 R2.
Problem is write performance at all. Sequential write is 18MB/s. I think that is caused by my wrong setup, I could not believe performance of that card is that bad, any cheap piece of RAID crap performing much better.
That card cannot setup write or read cache, there are "no read ahead" and "write through" enabled and cannot be changed - as far as I believe.
Sequential read rate is about 350MB/s which is pretty good - it is far much for my needs...