So, I bought three 3TB drives and made a RAID5 with them, despite numerous advices against it (there is even a society called BAARF - Battle Against Any RAID Four/Five). But, of course, I just had to see it for myself... With the "fake" onboard RAID controller (Intel ICH10R), I did not expect any stellar results. But the reality was even worse than I expected. First of all, it took two days to initialize the RAID. You can use the arrays before and during initialization, but the performance would be really abysmal. So what did I get after the long wait was over? Sequential read speed: down 27% compared to a standalone disk. Sequential write speed: down 44%. 512K block read speed: down 32%. 512K block write speed: down 88%. Ouch. 4K block read speed: up 4%. Probably just a statistical deviation. 4K block write speed: down 12%. 4K block read with queue depth 32: up 125%. 4K block write with queue depth 32: down 8%. I think I should go buy one more drive and make a RAID10.