in windows 7, the rate your computer bit, my system scores 7.7 all the way to the hdd, can you recomend a good hdd around 300gb that would improve performance above the 5.9 im getting, was looking at ssds but they are way out of my price range.
xfx 780i sli
ocz 8gb sli ddr2 @1000mhz
xfx gts 250 black edition x2
western digital 500gb 7200rpm
xfx black edition 850w psu
The issue really shouldn't be the rating, it should be whether you're finding the system to be too slow for your needs.
Without going to RAID it's pretty difficult to find a hard drive that will get much if any beyond the 5.9 rating. The only way to really get up into the 7 range is to use an SSD (Solid State Disk), which will also improve your boot and application startup times a whole lot.