How about trying these drivers? I use them and they are better for allowing 3rd party tools to work. Make sure you follow the website's instructions for a clean driver install. Also, FYI, when I did a clean driver install, my DVI ports did not work until I installed the new drivers, and an adapter didn't help. I had to use an old VGA CRT monitor for that step.
I know it says "7900 mod," but I think it's his latest updated drivers.
For GPU tweak, did you click advanced settings? It's the hexagon - it should be filled. Next, go to settings, and you should see "overclock range enhancement" - it may be ticked. UNTICK it, click apply, and then go back into settings, and TICk it, and click apply. That worked for me - the GUI just hadn't updated or something. I am using GPU Tweak 188.8.131.52 from the GPU Tweak website. Not an XFX Double D, but it may help.Edited by ElDictator - 5/31/12 at 6:50am