Documentation on the 4890 is surprising sparse and confusing. I have the VisonTek 4890 which I purchase because it has 2 DVI ports and no factory overclock which should make it a reference model.

Here is where I currently stand:
OSX 10.6.2
PC EFI 10.5

In System/Library/Extensions:

ATIx2000.kext
ATI4800Controller.kext
EVOenabler.kext

Both ATI ktexts have been updated and contain the 4890 0x94601002 ID.

I have installed them using Netkas' 10.6.2 QE Exotic Patch, and installed EVO using Ktext Helper B7.

Should they also be placed in /extra/extensions?

I repaired permissions.

In com.apple.boot.plist I have graphics enabled.

System Profile (In Safe Mode) Shows:

ATI Radeon HD 4890:

Chipset Model: ATI Radeon HD 4890
Type: GPU
Bus: PCIe
Slot: Slot-1
PCIe Lane Width: x16
VRAM (Total): 256 MB
Vendor: ATI (0x1002)
Device ID: 0x9460
Revision ID: 0x0000
ROM Revision: 113-B7710C-176
EFI Driver Version: 01.00.318
Displays:
Display:
Resolution: 1024 x 768
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Display Connector:

Here is my error message



The messages show are:

kxld[com.apple.kext.ATI4800Controller]: The vtable (Gives numbers/letters is corrupted/damaged) please check against the correct headers.

Can't load kext com.apple.kext.ATI4800Controller

Failed to load executable for kext com.apple.kext.4800Controller

etc, etc basically the same message repeated for 3-4 lines.

When I finally do get to OSX the screen is all garbled, a mix of white and black streaks and boxes.

Any help would appreciated.