iMac mid 2010 graphics issues after installing Yosemite

I've had this same problem since I installed the first Yosemite beta on my Mid 2010 iMac. I do have 12GB of RAM and I do not believe it is a RAM issue.

Like some of you, if left for a few days or weeks, suddenly the performance may come back.

I ran Quartz debug and FPS went from 45 on viewing the applications from the dock to 25 after a wake from sleep.

I performed a fresh install of Yosemite and erased my HD in the process, still the same issue.

I suspect that this is a bug in the graphics subsystem specifically on older Macs.

Apple needs to get this fixed as my iMac is not so much fun anymore.

gordon9291 reported in this thread:

Re: Graphics slow after sleep/wake

That OS X 10.10.1 beta fixes this issue.

I've installed the Beta also (to do this, you need to be a member of the developer program I think), and can confirm the problem is no longer reproducible. Hopefully this bodes well for when 10.10.1 is released in full.

Thank you for this information. Good to hear that they have managed to patch this in.

I'm sorry to come back with bad news, but having woken my iMac this morning after a good 12+ hour sleep, the problem is back :-(

I had same issue with 10.10.1

I did have my system periodically go from slow performance to better once or twice. When I first installed 10.10.1 the first wake caused performance problems, then surprisingly the last two wakes were running fine. I did also notice that when I get the slowness I get the WindowsServer Surface Testing Disallowed error in the console. After a wake where performance is ok I do not get those messages.

Perhaps this has something to do with memory allocation or restoring from or to memory during the sleep/wake cycle?

Today I tested force quitting the WindowsServer process. This forces a logout. Still no luck restoring my performance. A restart must clear the RAM and restart the service properly. Since periodically the wake from sleep suddenly makes the performance good again I will try successive sleep/wake cycles.

I tested wake cycling by putting my Mac to sleep then waking it back up. Sleep until you hear the 'click' noise of powering down then waking using bluetooth keyboard touch. After about 5 sleep wake cycles, suddenly my performance came back. I copied the console logs into a Word document. Later today I woke the computer again and performance was bad. I copied those logs into a Word document. I now have a full console of a good wake from sleep and a bad wake from sleep.

While there are some discrepancies, I am currently focusing on the WindowsServer processes. On the good wake from sleep I have one reference:

11/9/14 10:52:15.484 AM WindowServer[7657]: handle_will_sleep_auth_and_shield_windows: Deferring.

This is not listed in the bad wakeup sequence.

One more thing I noticed... If I wake from sleep using the bluetooth keyboard, I almost every time get the bad performance. I just tried several times back and forth and found that using the power switch on the back of the computer to wake the system resulted in good performance every time. My thinking now is that there are two wake from sleep procedures and the bluetooth procedure has a bug.

I'm hoping someone may confirm.

Well I have just tested your scenario, and after 12+h of sleep and wake up using a power button instead of a trackpad/keyboard, iMac woke up with no lag problems at all. I'll give this test a few more tries (over the next few days) and report back.

I've been testing this over the past day now. Overtime I start with the power button the system runs fine. When I forget and use my keyboard it lags. There are significant differences between a logon through the power button console logs and keyboard. I'm positive this is the issue.

Thanks again for your feedback. I'm sure I'll have the same results as you considering that I always wake up with keyboard/trackpad. Waking up with a power button is not a problem for me as long as I can use the sleep command. I'm sure it will be patched in the near future but for now this is great news.

Thanks again.

Can confirm same issue and same fix using the power button to wake. There's hope. This has been the bane of my gaming since Beta. Thanks all.

I have tried using the power-button trick here. It works, but only if the iMac hasn't already slumped into 'poor graphics' mode. Once it is in that mode (if I wake it by keyboard from a long sleep), nothing seems to get it out of that again except a restart. Sleeping again and using the power button doesn't recover it.

I've been able to put my iMac to sleep then wake up with the keyboard to force it into lag mode. By putting it to sleep again and letting the complete sleep cycle finish (until I hear the click of the iMac powering down), I can then restore performance with the power switch wake.

In my case I did a fresh install of Yosemite and updated to 10.10.1. That might make the difference.

Power switch trick definitely works (That is waking up the system via power switch). Tested it with my favourite game XCom which would always come to a crawling speed after a wake up and it's running at top speed now after a power-wake. I hope someone also informed Apple of this and that they are aware of this issue. It should be fairly easy for them to fix something like this. Though I imagine that this issue could be occurring due to the newer version of Bluetooth hardware they started using after 2010 iMacs, which is the same reason Yosemite handoff features don't work with our old iMacs.