How much do hard drives effect game performance??

I have been wondering about this for awhile, how much do hard drives really effect gameplay? Obviously I understand they effect loading times but once the game or level is loaded does it even matter?

they wont give you anymore FPS if thats what you are asking. all that loads into the RAM and VRAM when you play a game. as long as you have a decent 7200RPM hard drive you are fine for gaming.

When you are playing a game and loading it takes the data from the HDD and moves it into the RAM, if you don't have enough RAM then it will start swapping back and forth to the hard drive, killing your FPS. However the blow will be VERY SLIGHTLY lessened by your HDD speed. Just throw 4GB RAM in there and you'll be fine.