so I have a 120gig ssdrive. Its running out of room, if i were to go get another one, can I plug it in just like an extra hard drive and install diablo 3 on it. Or do ssdrives only work fast with the drive having the OS on it? computer noob question.
You'd be fine. You want the OS on an SSD so that the OS loads up quick. But there's no advantage to trying to access something that happens to be on the same drive as the OS vs a different drive.