If you're trying to build yourself a good gaming rig, the most important part of it, is the graphics card. Best to combine is high-end graphics card like the nVidia GTX 600 series or the AMD HD 7000 series with a mid-class processor like a AMD Phenom II x4 or Intel Core i5 or higher, for best performance. If you can't afford such expensive parts, you can keep the same algorithm with lower-class parts (Phenom II x2, Core i3, GTX 400/500, AMD HD 5000/6000), while still keeping the graphics card the most powerfull component.Make sure you invest in a good power supply, which has 80% efficiency or more.
That important because, your gaming rig will have an awfully high power consumption.
If the supply required sums up to 600W, and you get a cheap power supply with 70% efficiency for example, the intake will have to compensate for the 30% loss when delivering the actual 600W to the parts. Which means that the power supply will consume 30% more, or in this case, 180W more than it will actually use. Over time, these 180W will build up, making you pay a lot more money, than you need for getting a more efficient power supply.
