Photoshop CS5 GPU Detection on Mac Pro

Just downloaded the CS5 Master Suite Trial.

Here's my Setup:

MacPro 1,1 with ATI 4870 Driving a 24" LED ACD (Center) and a 20" ACD (right) AND the original 7300 GT driving another 20" ACD (left).

Under Preferences > Performance > GPU Settings, PS is only detecting the much weaker 7300 GT, and not allowing advanced settings/performance of the HD 4870.

(Previously, CS4 automatically detects the 4870.)

Anyone else with multiple/mixed GPUs having this issue?

EDIT: Came across this article on nVidia's site, the wording almost sounds like Photoshop favors nVidia hardware over other brands. I know its not too common to have mixed GPUs in one system, but I know there are other users that do on this forum...anyone....? Bueller?

So I was playing around with this a bit today, did some experiments to see if I could get the proper card to be detected.

I quit Photoshop, powered off and disconnected the monitor hooked up to the 7300 GT, restarted Photoshop, and it detected the ATI 4870, with much better performance I might add, zooming and dragging around a large layered PSD.

I could then re-attach the monitor and use my setup as normal. If I quit Photoshop and re-opened, it would again choose the weaker card, which indicates that the preference is re-set every time the app opens.

There is a lengthy Adobe KB doc that details GPU support in Photoshop CS5. Notice the long list of known issues with the GT7300 under Mac OS...