Dual GFX card annoyance...

[Firebar]

So I have a GT120 for use under OS X. It's been running fine on its own.

I happened to be given some store credit at an online retailer. I do a bit of gaming now and then so I purchase a GTX 470.

I'd like to run both the cards side by side, using the GT120 for OS X and the GTX 470 under Windows.

I've put the GTX470 in the bottom most PCI-E 16x slot, with the GT120 in the PCI-E 4x slot as the "helper" card.

I can boot into Windows and use the GTX 470 no problem, very happy with it I am too. However, if I boot into OS X with my display on the GT120 I get to the point just before the login screen. I'm greeted by the typical Mac light-blue background flashing every now and then (as if its probing for monitor res) and occasionally I see the 10.6 galaxy-type background. However beyond this it doesn't do anything else, it just sits there at this point.

Has anyone had this issue before? I'm at a loss as to how I can just get OS X to run with the GT120.

Thanks in advance :)

[CaptainChunk]

Have you tried the GT 120 in Slot 2? I can understand wanting to use Slot 1 for the GTX 470 (because it's double-height), but why exactly are you moving the GT 120 all the way up to Slot 4?

[Firebar]

As I'm typing this I'm experimenting. As you noted, I've just tried slot 2....

So it doesn't work in Slot 3 or 4. It DOES work in slot 2. Only problem is that its very close to the GTX470 - bit worried about ventilation.

Should note I have a 2009 Mac Pro.