There's an obvious OpenGL performance gain/difference. More apps have trouble with OpenGL in 10.6.3, so it could be failing miserably at something, which is showing as a performance gain. For instance Xcode's Core Image Fun House.app distorts and has the green problem whenever a filter is applied, but doesn't have this problem with 10.6.2. Photoshop still requires that Use For Image Display be turned off in Advanced OpenGL Drawing. I tried to do some OpenGL debugging, but I'm clueless when it comes to OpenGL, so it was rather pointless.
There are some reports of similar issues with retail Macs, see the Apple Support Forums. The ATI Radeon X1600 seems to be a popular card with reports of retail problems. If this is anything similar to the retail issue, then I'm inclined to believe that it has to do with the memory management in the ATI driver.
I don't know if this has anything to do with it, but without the ATI4500 kext loaded, my card reports 256MB of VRAM in Profiler, so perhaps it isn't using the VRAM properly. Is there any difference in the 45xx vs 43xx series when it comes to memory management? I tried using atMonitor to monitor the VRAM usage (suggested in the Apple Support thread), but I get a Kernel Panic (due to my using legacy kernel no doubt). If someone with vanilla kernel wants to give it a try, please report back if there's anything interesting.
@ANARCHiNTOSH: Nice work on the injection kext
hopefully to replace the GraphicsEnabler=Yes/DSDT injector.
It was really easy to make, i adapted the concept from a similiar kext for GTX295, which also needed a device-id injected.
All thats inside is a plist that overwrites a part of the ATI4500 kext plist. (a lot like LegacyHDA.kext does for AppleHDA.kext)
i tried atMonitor and it worked, but im not really sure what im looking for?
nothing particularly remarkable struck me, apart from getting no reading from gpu usage or gpu temperature (which isnt particyularly surprising on osx86).
vRam seemed all right, never really rising above 30% usage though.
apparently 4550 users are having the same problem:
i think to fix the green all that needs to be done is find the offending code in the offending kext and overwrite it
with the 10.6.2 code, which can be done either manually or with the injector kext (legacy style).
shouldnt be too hard, its just finding the code which is timeconsuming
if you want the green apple and OpenGL errors fixed on 10.6.3, follow the steps in post 100 to help me find out which kext(s) is causing the problem so i can correct it from my ATI4350.Fix.kext