Would you like to know if your system will run a game BEFORE you buy it ?.
Of course you would, you dont want to spend your money on a game only to find out after installing it , it won't play on your system.
Here is a neat little site, it will tell you if your game will run, and what sort of performance you can expect on your system.
Can You RUN It?
Hope this helps, and save's a bit of cash, and stress.