It depends on what game you play, if its one of the newer games which are pretty graphics intensive then yes you would notice the difference, with older games there probably won't be much difference although if you're having to play them at lower settings to get them to run you could set all the settings to max and get a much faster more fluid and detailed game. As far as I know there is a minimum requirement for speed of your processor and for amount of memory you should be able to get the info about this from the Sapphire website. One thing you may need to do is buy a new power supply, the newer graphics card come with a seperate power supply connector(same as you plug into your hard drive) as the AGP port cannot supply enough power on its own. You would probably need a 400watt power supply although if you have a good make 350w one it might be ok. The only way to know for sure would be to try it but if you power supply is 300 watt or less then you will definately need a new one. Heres a link to the brochure for the card click here and it includes the minimum specifications.