Doom 3 wont be out for another 2 years, You will be needing an upgrade anyways by then. Plus, in 2 years, AMDs will probally have SSE2 instructions (the A4 will have SSE). I dont think I would make a CPU choice over this factor. Im not saying the P4 wont make a Sweet ride, it will, just this shouldnt be you deciding factor, IMO.