Hey all, not that anyone should care but i recently bought a new machine. The new 2012 imac with the nvidia card. I couldn't deal with the artifacts problem anymore while using my computer for work so I decided to upgrade. However I am still trying to figure out the problem and have compiled a list of personal notes that may or may not be helpful to anyone with our problem. I will still be testing/trying to figure this problem out as I am certain that it is not hardware related and must be driver problems. Right now i'm waiting for 10.8.4 to be released to see if this does anything. I do recommend that anyone with this problem write to apple and mention this support thread and include as much information as possible. For a company that is built around hardware and software being locked together we shouldn't be experiencing this at all. They made the choice to include the ATI cards in their iMac product line and should fix/offer support to this problem. Anyway, here is my unorganized compilation of notes.
Graphics Artifacting in OSX w. ATI graphics cards.
Known Systems affected.
-2010 iMac w. ATI Radeon HD 5750
-2011 iMac w. AMD Radeon HD 6970M
Other systems have been reported to experience the GPU artifacting as well. These two cards are the most known and commonly affected.
Different builds of the OS produce different results. This leads me and many others to know that this is a software problem.
Graphics artifacts are NEVER present in recovery mode and new OS installation mode?
Graphics artifacts show up on PRINT SCREENS and external displays.
Johann P recomends NEVER putting the display to sleep as this replicates the artifacts pretty quickly.
I have personally experienced the problem in later builds of 10.6 through 10.7 to 10.8 as well as many others.
Andrew Humphreys had come up with the first originally temporary solution. This involved flashing the GPU BIOS settings. The original power play settings were 157/300. In his fix the settings are changed to 400/900. Some have had limited success increasing their idle voltage from 0.95v to 0.96, 0.97 or 0.98. Personally I increased my voltage to 0.98. All of the information on this fix is originally documented at this link. https://discussions.apple.com/thread/3194165?answerId=18398448022#18398448022 (It should be noted that this fix is only a temporary solution. That may last weeks or months.)
The two main Apple support threads documenting these problems are:
https://discussions.apple.com/thread/3194165?start=0&tstart=0
https://discussions.apple.com/thread/3199218?start=0&tstart=0
Apple has been made aware of this problem on separate accounts. I have personally contacted apple by sending an email directly to Tim Cook. I had then been contacted by an Apple executive representative and support technician who were working with apple engineers. At first they seemed very interested in my specific problem. They had even originally agreed with me that this must be software related. After a few days with no new answer Apple’s “Engineers” concluded that it was hardware related. They had wanted me to take my machine to an apple store to replace my GPU. I disagreed with them and did not take my machine in. The reason for not taking in my machine was because it was my main computer needed for work and I could not be without it for the estimated 4 days of service time. I also was reluctant to bring my machine in for a graphics card replacement because many users in the support thread have done the same to no avail. Many users experiencing this problem before me have had their GPU, PSU, Logic board, and Display replaced and have noted that the artifacting/graphics problems still existed.
All in all the problem is either error in design or driver related. These ATI cards are not agreeing with OSX after extended amounts of time and someone does not want to admit this.
I would like to compile as much information on this subject to help the users experiencing these problems as well as lead people away from buying any machines with the problematic ATI cards.
My Personal notes on 27” iMac w/ ATI Radeon 5750HD running in OSX.
Andrew Humphrey’s Original Fix (This fix only lasted a few months.)
GPU flash of power play settings from 157/300 to 400/900.
Also voltage increases from 0.95v to 0.98v
Print screens show artifacts as well as external displays
10.6 (This is where I originally experienced the artifacting. at this point in time I did not take notes on the builds that were affected.)
10.7 (Artifacting was similar to 10.6 if not better or worse. I did not take careful notes.)
10.8.0 (untested, however Andrew has reported originally that this build was stable but over time went bad.)
10.8.1 (untested)
10.8.2 (This build was stable for quite some time until an unknown problem occurred which lead to artifacting.)
-Disabling the dock magnification feature improves stability and lessens artifacting. Does not completely fix the problem. (This can probably be explained due to the immediate change in the GPU clock cycle.)
-Resolution change. Less artifacts at 1920 x 1080.
10.8.3 (completely unstable/unusable (AppleGraphicsPowerManagement.kext was introduced which undoes the original BIOS FLASH fix)
10.8.4 (I am hoping that this build will have a fix as I have heard that it is focusing on graphics)
