Radeon HD 3870 not working properly

Hi all,

I just picked up a Powercolor Radeon HD 3870 yesterday, got it all setup, only to find that it's performing basically on par with the X800 Pro I had beforehand. Here's my current setup;

Asus M2N-E
AMD Athlon 64 X2 3600+
OCZ Gold ddr2 2GB
Powercolor Radeon HD 3870
Antec Neopower 500W psu
Win XP Pro Sp2

Anyhow, I uninstalled the old catalysts, ran driver cleaner, popped the card in, installed the new ones (7.12) and discovered that my fps was absolute crap in WoW, TF2 & 3dmark 06 was basically a slideshow -- surprisingly hellgate london performed fairly well. Anyways, its working about the same as the x800 pro did. So, I removed the drivers and went with the ones that came on the CD with the product, however, I got the same results.

Anyone know what I should do here ?

Cheers,
-Earth