After running a few test, it appears that I need to upgrade to be able to use RAID5 effectively. I get acceptable performance from RAID0/1, but RAID5 is basically falling off a cliff. I get good sequential read access (to the order of >200MB/sec), but sequential write provides the same performance as random read/write (<10MB/sec). Configuring RAID1 gives decent perf, about 140MB/sec sequential read/write and almost 10MB/sec random. This is on a S5520HC motherboard running W2K08R2 with RAID driver version 188.8.131.52. Disk test run with PassMark PerformanceTest-64bit.