XFX Radeon HD 5670 Going Black at Reboot

Hope y'all can help. Here is my build:

ASUS P8H67-I Deluxe
i3-2100T
GSkill 4 gig
XFX 5670 as in title
WD Scorpio Black 320 gig
HP dvd1270i

I get all the way through with OSX update 10.6.7 then Bridgehelper 2.1 then Multibeast 3.8 (with easy DSDT) and reboot. Upon reboot I get an Apple and a little spinney thing beneath, then about 15 seconds later it all goes black. Fans are on but nothing on the screen.

I then go back and re-install OSX 10.6 retail .....Multibeast. Up to that point it looks like the OS is working. Then black screen after reboot. It is annoying because I cannot edit after this.

Any ideas?

I had similar issues with XFX 5670:
viewtopic.php?f=79&t=18806

Maybe it will help.

Try adding this to your com.apple.boot.plistbig thanks to grtitan)

string>arch=x86_64</string>
<key>PCIRootUID</key>
<string>1</string>
<key>GraphicsEnabler</key>
<string>Yes</string>
<key>AtiConfig</key>
<string>Duckweed</string>

This worked for me. I had the same problem when booting with just PCIRootUID=1; screen went black just before it reached the desktop. I then had to unplug it from the DVI port and plug it in again for it to work. Give this a go, it won't cause your system to crash - if your framebuffer is displaying correctly then you can drop the last two lines. You can check this in "About this Mac" under graphics card or in Terminal by typing "ioreg | grep ATY

Thanks folks! I am still working at it.