timmmay: RAID 0 with an SSD sounds risky. Also I read the Intel disk controller on motherboards can't keep up with raid'd SSDs, you need a better controller to do it.
Well it was coping fine with 3, but with 4 it just wasn't seeing the potential. The ICHR10+ controllers from Intel max out at about 465MB/s
I got another controller and now I can fairly often sustain over a GB a second transfer rates.