First of all thank you for the quick reply Everything in D.Manager is fine and i was achieving some amazing speed in HDTach. Burst speed was 250MB/s, squential read average around 120MB/s, random access was 13.2 & read speed was 94MB/s. Just that the CPU utilization rate skyrocketed at 8%. Also i did reconfig the array, but still i can't format the hdds, either in RAID or in single drive mode. But i can do that on the other machine with the same drive. I had BIOS v. F4 loaded n was installing with NV package for X64, 6.66. So i guess it may be the problem of the MB? My ram did work fine, it was the corsair VS 1GB CL2.5.