EDIT with sort of fix:
Apparently Apple only supports DVI output on a PCI card. I unplugged my VGA monitor (with adapter) and now the card works.
So I plugged the VGA monitor into my laptop VGA output and it works with all 3 screens. Although it's a little inconvenient to switch cables around for booting another OS, this is pretty cool.
What I don't understand, is that VGA worked fine when I was on Leopard. Did they actually decide to remove functionality in later versions?
I'm going to keep working a bit on it and see if I can drive both monitors with the eGPU.
Hi joshhh, following on the conversation about using an eGPU - I've managed to get hold of a PE4H and done some testing with a GTX260. While it works well in Windows and Linux, Mountain Lion does not want to play nice with it. I'm not entirely sure if it is possible at this moment, although I am making threads in other places asking for advice.
The funny (and frustrating) thing is, the GTX260 is detected and listed in System Information along with the NVS, but none of the displays are detected and the vram is listed as being 1MB only (which may not make a difference, but it is a bit strange).
Here though - http://www.tonymacx8...html#post409185
it suggests that someone has got it all working with a very similar setup, the difference being that the internal graphics card is Intel and ours is Nvidia.
Of course, booting up with the Intel card enabled instead in BIOS does not work at all for me.
This thread - http://forum.noteboo...xperiences.html
suggests that the device ID must be added to NVDAGF100Hal.kext, but that hasn't helped for me (besides, the card is already detected, just not working).
I've had this GTX card working in Leopard before (after installing Nvidia drivers which should all be included in ML now) so I can't see any reason for it not to work, but it'd be good to do some more testing and see if it is actually possible, especially before people go out and spend money on their own eGPU setups.
I'm wondering if something needs to be added to the dsdt file, but that is beyond me.