the performance is no deference than Pentium D 3.0 in most apps.. ( the deference in some games, rendering and encoding).. .
This is basically everything that uses a CPU. If games, rendering and encoding is faster, what is the P4 faster at, other then heating the room?
If you don't see a difference between one or two X2s, you need to bump the resolution up. You shouldn't be using 2x X2s if your gaming at 1680x1050. A single card is fine. Next time do your home work and don't just buy stuff thats expensive thinking its the best.