What I read here is that the speed-up from using RAID0 over none is small, even for gamers. To optimize your speed you would be well advised to ensure you have enough RAM so that Windows (or whatever OS) has space to cache some files there. Of course, you must have better than 1GB or RAM to do gaming at all, anyway, so you can avoid running to the Virtual Memory on the HDD.
Real experience from gamers, with actual measurements if possible, could help here, though. that's not me.