So I decided to take my bosses old Samsung 52" LCD HDTV off his hands, and use it as a dual purpose monitor/TV, which is amazing. I'm totally happy already... in windows. OSX will not boot. Have tried Lion (10.7.3) and Snow Leopard (10.6.8). It goes to the apple loading screen, then goes black. I know the OS is working because the hard drive light stops blinking where I login, then I blindly enter my password, then the hard drive light goes crazy again for a min or so then stops. It boots if I disconnect the TV and hook up my old 22" LCD.

I'm thinking maybe its the adapter cable I'm using, I know OSX is very picky when its on a PC. The cable is a HDMI to DVI. Weird thing is the cable worked fine on my old GT240, but it was reverse the way it is now. the way it is now, is the DVI is in the PC, the HDMI is in the TV. it was reverse on my old system... (dvi was in monitor, HDMI was in PC)

The TV has a VGA input, but the 9800GTX doesn't. Dual DVI only.

Any of the Geniuses here have any idea? Graphics Enabler issue, perhaps? Maybe add strings to boot.plist? Get the .rom file for the macpro and point chameleon to use that rom instead of the onboard rom?