I'm getting an XPS 430, with the default graphics card (Radeon 3450). I'm planning to step up to a 4870, or GTX 260/280. But is it compatable? Whats the power supply, and does it have a PCI- Express x16 2.0 slot? I know it will fit, but i have to make sure. If i just buy and replace the old one, am i good to go? Please help, since i know a lot of people might be in the same situation.