Ok, so having no answer on my previous post on my iDeneb install, I thought I give a shot to the latest iPC release.
And it turned out it worked out very good, close to my previous experiences with JaS, XxX and Leo4ALL. All went fine and smooth and I am so much close to being a happy user again.
But I got the very old problem with the CI/QE. It was much too beautiful to be perfect ...
And as this forum changed a lot since my last visit, I find myself lost trying to find help on how to enable QE on my card. Once there were some sticky posts on trivial problems like mine but it seems that those posts vanished.

So, I need help to enable QE on iPC 10.5.6 PPF5 FINAL, using the 9.4.0 Universal kernel.
During installation I chose to install the "ATI Radeon HD 2900" provided drivers (I will try a new installation using the provided "Natit" too right after I end this post, just to make sure, but I have the feeling it won't help me too much)

The "About ...." now shows like this:

Chipset Model: ATI Radeon HD 2900
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 512 MB
Vendor: ATI (0x1002)
Device ID: 0x9400
Revision ID: 0x0000
ROM Revision: 113-B1480A-236
EFI Driver Version: 01.00.236
Displays:
SyncMaster:
Resolution: 1680 x 1050 @ 60 Hz
Depth: 32-bit Color
Core Image: Software
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Not Supported
Rotation: Supported
Display Connector:
Status: No display connected

... and I really hope this time someone will bother to answer.

i have a ATI radeon hd 2600xt and i have the same problem as you

I, i have a Radeon HD2900XT 1gb and install ideneb 1.4; 10.5.6, all ok, just video, bu in this post
http://www.insanelymac.com/forum/index.php?showtopic=94090
Supported Radeon HD cards:
Radeon HD 2400
Radeon HD 2600 Pro, Radeon HD 2600 XT
Radeon HD 2900 Pro, Radeon HD 2900 XT
Radeon HD 3850
Radeon HD 3870
Radeon HD 3870x2
explain how to install and work full, just install kext on your system and ready.....
Works for me i have full QE CI, hope to help u.....

HOW?? dont work on my 2900xt 1gb
in sys profiler it says 256mb, on efi studio max 512mb - no any method work just black squares

Having a heck of a time getting my 2900 HD pro (512) to work correctly. Right now I have everything working except quartz extreme and core image. =(

When I try Efi Studio, or the ati package, I get either a black screen or all the squares/garbled graphics. I forget which for which, but it no worky Help?