Flashed xfx 4870 zdfc v.e problems

I flashed this card according to pimpmolo instructions. The card boots and functions properly in both osx 10.6.4 and windows. However, I do have issues when playing graphically intense games. It doesn't appear to be a heat issue because a game might run for several hours or 30 seconds. When the card hangs the screen displays the image on the screen when the lock happened with an overlayed checkerboard pattern. At that point I have to power off the machine. Can someone look at my modified rom that I flashed to double check?

 

Details,

Mac pro 1,1 dual 2.66Ghz dual core.
3gb ram.

The game I'm trying to play is World of Warcraft.

xfx video card is the only one in the machine x16.
Card is powered from the two special cables that attach to the motherboard.

Display is single link DVI, I also have a Dual link connection to a 32" HDTV DVI.

What other details do I need to provide?

I though I attached both the RV770.bin and my modified version but it didn't show in my first post.

Thanks for any help in advance.

 

Also just noticed the Preview.app display window is blank now after 10.6.4 update

 

So the 10.6.4 update killed my QE that was previously working on 10.6.3