If you have 2gb of ram, your video game should be able to load itself entirely into memory(you'll notice a difference then). Running your programs off of a raptor is only going to make them load 1s quicker. The difference is roughly 10-20mb/s. Ide drives usually get 48-52mb/s, Satas (believe it or not, ive got the benchmarks to back it up) are actually SLOWER in a single drive configuration than ide drives. You'll get like 45mb/s off a standard 7200rpm 8mb cache sata drive. Once you pair them in raid 0 you'll get like 70-80mbs. Raptors are quicker, running at 60-70mb/s as individual drives. But their price makes them an ineffective os drive. I have 1gb of ram in my system, games like HL2, starwars galaxies, and counterstrike never have to load anything off my drives. Besides of course, the initial load into memory.
my suggestion, dont waste your money. Get an 80gb ide 7200rpm 8mb cache drive for your OS and games/programs.