im quite new to all this and i cant quite get my head around meroys instructions!
im not sure where id get hold of the NVDANV50Hal.kext ....
im running a retail snow install on a GA-EX58-UD5 using Digital dreamers script,
it currently shows up in system profiler as having only 32MB of VRAM, and i know that isnt right!
snow leopard with a GTX295 would be wicked
It is indeed wicked.
I too used d_d's script, albeit with a Gigabyte GTX 295 (rev 2.0) and a GA-EX58-UD4P. The first time around, I made the (apparently quite silly) mistake of force-installing the EVGA drivers for OS X 10.5 and trying (but failing) to install netkas' graphics enabler.
It turns out that netkas' enabler is already built into his PC-EFI tool. What I did was choose Chameleon 2.0 RC3 bootloader from d_d's script (this requires a DSDT file in your /Extra directory) and replaced the /boot file with PC EFI v 10.3. I then turned on the option in the /Extra/com.apple.boot.plist for GraphicsEnabler = yes. This caused boot-up to hang as it recognised a video card, but could not find drivers for it.
To solve this, I edited the Info.plist in NVDANV50.kext (in /System/Library/Extensions) and added my device id 0x05eb10d0. The system now booted successfully, but showed "Display" and "Unknown" as the graphics adaptors. I finally turned off the graphics enabler and instead opted for the EFI string as meroy explained, which gave me great joy as it provided the correct information in System Profiler.
Just a short while ago I updated to 10.6.1 and my computer would hang at boot up. I confirmed my suspicion (using my Macbook) that the update had modified the NVDANV50.kext file. I then switched to the alternative of using Rph4's NVGTX295.Fix.kext in my /Extra folder. This allows for a nice vanilla Snow Leopard with complete GTX 295 support.
(Sorry if this was long-winded, but you might find this account of what I tried and how it went wrong useful!)