Early 2008 Mac Pro + ATI Radeon HD 4870 = Not working

Question

Just took delivery of my new HD 4870 video card today. I installed it in my Early 2008 Mac Pro and booted up. I got a picture no problem on one monitor, but nothing on the other. Furthermore, the display perfpane was missing a lot of controls, like Arrangement and Detect Displays and whatnot.
I did a bunch of rebooting and swapping of cables, and determined that both the mini-display port and the standard DVI connection will drive a monitor. However, if both are plugged in, the only active display is the one plugged into the mini-display port, and there's no option to setup the secondary display.
So I booted into bootcamp, and it automatically recognized both display ports, and mirrored my desktop on both monitors. I downloaded and installed the latest windows drivers, rebooted the machine into windows once more, and was able to configure a multiple monitor display with no problem.
This tells me it's not the card and it's not the motherboard.
Booting back into mac OS, I discovered that it doesn't even recognize that the card has video ram. It thought I had no video ram in the system.
So, this all leads me to the conclusion that Apple shipped me a card that it has not yet provided driver support for.
Hey Apple, can I have my 4870 display driver now?

Answer 1

Hi again,
It was funny to read all your answers on my iPhone while away from my computer. I could have reply on the iPhone but I preferred to wait to give you all the procedure I used to install the beta driver successfully this morning.
To start, I found this link:
http://www.insanelymac.com/forum/index.php?showtopic=155477
and followed the "4870 INSTRUCTIONS", starting like suggested by doing the "First, follow the 4850 INSTRUCTIONS above"... (See the link)
I would like also to specify that I did this without having installed the card physically yet. So I kept my HD 2600 in the computer, followed all the steps excepted for the step 3:
3. Reboot with -f -v (kextcache/verbose mode)
There is no -f nor -v switches available for the reboot command at the shell prompt. I simply rebooted as usual "Pomme -> Redémarrer".
After the reboot, all my software was still working as expected with my HD 2600 card, meaning that these steps are specific and active only for the HD 4870 when it's detected at boot-up.
You may have to Google for the string "Kext" in order to get the application to install the file ATY_Motmot.kext. For your information, ATY_Motmot filename is the same string as the one found under "System Information ->PCI cards" under "Name".
I get:
ATI Radeon HD 4870:
Name: ATY, Motmot
The article is not clear regarding where to find the OpenGL.framework to backup before installing the downloaded one. I found mine under:
/Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/OpenGL.framework
After having shutdown the computer, just after the reboot that proofed everything was ok, I removed the original HD 2600 card and put back the new HD 4870 and boot up...
Then I check the "System Information" and found both "Quartz Extreme" and "Core image" supported!
I launched Aperture, got it!
I launched Final Cut Express, got it!
I launched Starry Night Pro Plus, got it! Then I checked the OpenGL settings in Starry Night Pro PLus and activated both options:
Use shaders where available
Use AllSky shader (Not compatible with all hardware)
When I was doing these actions with my original HD 2600 card, the software was giving me a warning that my hardware did not support these options and that it could crash.
This time, with the HD 4870, it accepted my settings and give me back a very beautiful blue sky with much more shades!
So in conclusion, it works very smoothtly with my system and I am writing this with two monitors, having bought the MiniDP to DVI adapter this afternoon
I am happy!
P.S.: A girl from Apple support called me back this afternoon regarding my problem. She was very happy two when I told her that I did apply the beta driver and that it was working very well...
Good luck and best regards...