They do make a special port that can handle the demands of high speed graphics. Its called PCIX, its quite wide and they put it on very very short wires right next to the CPU and RAM, so they can get high speeds out of it. A PC has the power to run playstation & xbox360 games, its more that its easier to write games for one set of hardware. The USB powered games will be far far shittier. They will have terrible graphics compared to anythign else on the market. Other people have tried to provide a "better game" if you buy the hardware. Ageia did this with physics accelerators. Hardly anyone bought them, so nobody really made games for them. Seriously, I bought a 9600GT the other day for around AU$150. How cheap did you expect to make this for?
Mark Churchill Director Dunn & Churchill Free Download:
Diamond Binding: The simple, powerful, reliable, and effective data layer toolkit for Visual Studio.