Right, I'm in a bit of a pickle.

I previously had my Nvidia 8500GT 512mb working via EFI Strings, on my old Biostar AMD Mobo on Snow Leopard.
Now, that i've switched to an Intel Asus P5KPL-AM EPU, the same EFI strings seem to make no difference to anything, and it will only show up with 1280x1024 rez in VESA mode (i think)
It shows in the information bit, but only as 32mb, and not NVIDIA Geforce 8500GT and all the EFI strings malarkey, like it did on my previous mobo.
I've done a retail install, using the Snow DVD.

What am i doing wrong?

I have same problem. I tryed EFI string in com.apple.Boot.plist, and editing DSDT with code from this forum and nothing is working for me. If you find solution please post here.

have you tried using the -pci0 boot flag?

With dsdt or efi string?

Interesting.

I've tried, using -pci1 but it keeps saying "out of range" on my monitor.

Will give this a go.