You will not get any increase in fps if that is what you are thinking. If anything you will drop your fps and strain the heck out of your PCI bus, probably create some IRQ conflicts along the way and also bring your PSU to its knees as well. Using 1 extra PCI card for a second monitor or maybe even a 2nd PCI card for a 3rd monitor is cool, but thinking that it will make for better fps in games isnt going to happen. Besides, you would only be using the extra cards to produce a section of what is onscreen if you used multiple monitors, and you generally need them all to be the same brand and type of card to get good results.