Currently Being ModeratedSep 17, 2012 4:29 AM (in response to Roelof2)
try my fix here on page 5
As this issue tortures mac users for many years now, seems like apple programmers don't care about fixing it at all.
Currently Being ModeratedSep 17, 2012 7:48 AM (in response to Mac Admin1)
Changing screen resolution doesn't make any difference with the ATI Radeon cards...
Currently Being ModeratedSep 17, 2012 7:58 AM (in response to neslein)
neslein: then how do you explain that opposite what you say, it does a difference?
I have a Radeon HD 6870, and yes, changing the resolution brings back the performance.
Currently Being ModeratedSep 18, 2012 8:24 AM (in response to Mac Admin1)
On my 10.7.2 I have only one resolutionAnd that bug fix there didn't help too. Maybe there are some ideas what to do next? (no, i'm not going to upgrade)
Currently Being ModeratedSep 18, 2012 8:32 AM (in response to JAUG)
JAUG > may I ask what king of mac (hackintosh?) you own that has only one resolution available?
I've never seen such a thing. And what monitor you have? model no. etc.
Currently Being ModeratedNov 4, 2012 1:10 PM (in response to Kersten Lohmeyer)
I have an Apple 30" Cinema HD display connected to a Radeon HD 5870 1GB in a MacPro3,1 running Mountain Lion. Changing the screen resolution did not restore OpenGL performance for me after waking from sleep.
I figured that if changing resolutions is supposed to fix the problem, then perhaps the thing the fixes the problem is that the Radeon timings (pixel clock) are altered/recalculated/reset/whatever whenever the resolution changes.
But all the resolutions for the LCD display are scaled resolutions which means the Radeon is always outputing 2560x1600. The framebuffer is of different sizes but the output timings are unchanged.
Therefore, the solution might be to create a custom resolution (using something like SwitchResX) which is not a scaled resolution. The EDID of the Cinema HD display says it supports 1280 x 800 @ 59.910Hz and 2560 x 1600 @ 59.860Hz. I used SwitchResX to add a 1280 x 800 @ 59.910Hz non-scaled resolution and restarted the Mac.
Now when I wake the Mac from sleep, I can use that 1280 x 800 non-scaled resolution to restore OpenGL performance. It works.
Note that the Apple graphics drivers will not allow both a scaled and non-scaled version of the same resolution. When I add the non-scaled 1280 x 800, I can nolonger use the scaled 1280 x 800. The difference between 1280 x 800 scaled and non-scaled is that for scaled, the graphics card does the scaling and adds filtering to the pixels making them blurry and outputs 2560 x 1600. Non-scaled outputs 1280 x 800 and the Cinema HD itself quadruples the pixels to 2560 x 1600 without filtering (making them very sharp and crisp).
Currently Being ModeratedDec 18, 2012 8:12 AM (in response to Roelof2)
I have a 2008 Mac Pro (3,1). NO PROBLEMS until I upgraded to Mountain Lion. Now I have get weird pixel glitches followed by constant freezes. Looked at my crash log and sure enough its taxing the GPU too hard and its bugging out.
DO NOT upgrade unless you have to. Not sure if even an upgraded graphics card is gonna help my machine. And they are so expensive now anyway, not sure it's worth it.
One temp fix I've been using is downloading SMC fan control and monitoring internal temp of my Mac Pro and raising the fan speed. Its actually cooled it down so that I can work outside of safe mode. But obviously, not a good permanent fix.
Really frustrating they aren't supporting machines that aren't even that old. Trying to obsolete everything. So many mistakes from Apple lately. Very frustrating.
Currently Being ModeratedDec 18, 2012 8:18 AM (in response to radracer)
My 2008 Mac Pro works perfectly well under Mountain Lion with NVIDIA graphics. Had to replace graphics card after Lion came out and brought slow performance after sleep for ATI owners. What you describe looks more like a hardware problem. Could be fan failure or too much dust on your graphics card.
Currently Being ModeratedDec 18, 2012 8:50 AM (in response to ViktorCode)
Did a pretty serious cleaning of dust from my machine, so I'm fairly confident that's not the issue. Fans had no problems until Mountain Lion.
What are the specs on your NVIDIA card?
Currently Being ModeratedDec 27, 2012 3:16 PM (in response to Kersten Lohmeyer)
Im pretty clueless when it comes to computers. I own a 2008 iMac with
Processor: 2.66 GHz Intel Core 2 Duo
Memory: 2 GB 800 MHz DDR2 SDRAM
Graphics: ATI Radeon HD 2600 Pro 256 MB
Software: Mac OS X Lion 10.7.5 (11G63b)
I had the Harddrive crash and replaced last summer, and had the graphic card needed to be replaced. I after the graphics card being replaced all everything graphic wise is slow/choppy. I don't want to buy a new computer unless i need to. Any help/suggestions would be nice.
Currently Being ModeratedMar 25, 2013 8:53 AM (in response to StevenLei)
Apple says the issue I was having was fixed in 10.8.3. I no longer have a performance slow down after sleep with my ATI Radeon HD 5870.
Currently Being ModeratedMar 25, 2013 12:08 PM (in response to joevt)
Hey, you're right! Finally! No more performance degradation after sleep - everything just runs as smooth as it should! Thank you, Apple - what took you so long? Now I can actually use the sleep mode on my Mac Pro 3,1 with the ATI 5870 card again! Problem solved!
Currently Being ModeratedMay 8, 2013 2:32 AM (in response to neslein)
I'm getting nasty screen glitches even after upgarding straight from Snow Leopard to Mountain Lion. I now have ML version 10.8.3 but they are still there. My iMac is a Mid 2007 model with the ATI Radeon HD 2600 Pro 256 MB built in GPU.
Could my problem be due to overheating? Can anything be done about this?
Curiously the artifacts don't show up if I'm booted in Safe Mode.
Currently Being ModeratedJul 12, 2013 3:07 PM (in response to Kersten Lohmeyer)
It's slow for me. 2008 Mac Pro with ATI Radeon HD 2600.