3000W? That would be a server or something, but even then, I don't know of a server that uses 3kW of power on it's own?! There's probably a mistake on the site. I looked at ur PC on Dell's site and it has a 230W PSU, so you will need a new one. But sadly, you'll have to cut away part of the casing at the back to allow a third-party PSU to fit into the case, since the one provided by Dell is proprietary. But if you can afford it, this PSU is made for ur PC specifically by PC Power & Cooling Inc. and you won't need to cut anything at all. And I don't think you need to get the X1300, since the 6200 PCI is cheaper from a performance vs. price standpoint.