BTW - From the original mail comments, it seemed like this might be a copy of his post in some forum (?). There's threads on this subject at MacRumors, IM, Netkas and apple's forums I think.)

My hardware: Mac Pro 2008 with a new Radeon 5770 video card and 30 inch Apple Cinema Display.
(Apple only lists 2009/2010 Mac Pros as supporting the 5770/5870 cards, although I'm sure you've seen the many posts since their intro these cards have been used in older Mac Pros with proper OS install/support. The first reports used a cloned 2010 Mac Pro OSX install.)

(From the following I assume Don either wanted to do a "Clean" install of Snow Leopard, or had 10.5.x installed on his Mac Pro.)

1- Even though the spec on the card reads 10.6.4 required the OSX 10.6.3 DVD does boot the Mac Pro and get to the language screen. (3D accel support requires later OS X than 10.6.3.) The installer works (btw user can invoke command+L to view the installer files as the install is progressing, one must use commonsense when reading those logs entries) and the restart happens without a panic or grey screen.

2- in the installer log there is mention "display is not using Open GL Acceleration". (10.6.3 doesn't have updated ATI kext for 5xxx radeon support.)

Restart after install:

3- once the Mac Pro boots initially after the OSX 10.6.3 install, the WELCOME setup screen with music appears but not the visuals of the stars and languages (I don't know what specific name to call that visualization). This is certainly unusual but acceptable to my needs. I think its because Open GL is not present for this card under OSX 10.6.3. (3d/accel support for the 5xxx radeons is only in later OS X versions. This is why apple lists 10.6.4 or later.)

4- if user looks at ASP during the boot of the install DVD under Graphics/Displays there is no information about display connectors, it's blank.

5- checking the Display pane under System Prefs show very little information: only one resolution, no Display name and no options. This is most likely because the Display profile needs updated after OSX 10.6.3

6- ASP shows no mini display (port) information, I would think if I had the newer Apple Display with the mini connector that the OSX 10.6.3 DVD would maybe boot but there would be a black screen which would provide serious difficulty to continue. This is a question that someone else can explore. I know in the future I'll own one eventually.

7- Snow Leopard is so much better at compatibility with different types of hardware than Leopard (10.5.x)... I think Leopard for me is in the past.

OSX 10.6.5 install: (Here's a link to the 10.6.5 Combo Updater as many of us prefer to use the D/L rather than software update.)
8- install and restart is ok.

9- Display pane under System prefs is now showing normal (all resolutions are present, the Profile name is specific and Options are present). I know this is elementary but I'm assuming Open GL Acceleration is present now but how does one determine that simply? I checked logs, ASP etc where is it determined? Windows server log seems to show Open GL install.

10- ASP now shows Display Connector status normally.
(FYI - a reader with older Mac Pro previously reported issues with MDP audio (using MDP Cinema Display), saying that even with 10.6.5 combo update install MDP audio was not working. As if some file (or version/update) was present on the 2010 Mac Pro installs that are not in even the 10.6.5 combo update. Not sure if his experience is common, but welcome other feedback on that.)

11- sleep functions normally.

Other thoughts:
Radeon 5770 is very quiet. There is ONE power connector to the card. At the Apple store people were mentioning two. (The 5870 model uses 2 (as did the 4870 and Geforce GTX-285), but the 5770 only uses 1, which is why apple lists ability to run dual 5770's. (Mac Pros to date only have two Aux power connectors (6-pin) although one reader used Y adapters to run 4 (for simul 4870 + GTX-285 use, which isn't recommended). More aux power connectors (and 8-pin) were on our Mac Pro wish list but apparently still only 2 (6-pin) in the 2010 Mac Pros.)

I think those of us who are using the 5870 or the 5770 in a 2008 Mac Pro are safe with future OSX Snow Leopard updaters since those cards are supported in newer Mac Pros and the Display profile must be made current with each update release.

Lastly, I don't mind doing these types of trials. Its been my interest and hobby for 25 plus years in the Mac world. It just becomes easier to do but more complicated because of the lack of acceptable information out there in the internet. I like to understand what I'm getting into when I decide to do major upgrades to a machine which is not current with the release versions of software updaters.
-Don H.