iMac 5K Retina extremely slow Mission Control

I had the same issue. Mission Control was extremely laggy on my iMac Retina 5k with i7 + 290X + 3TB Fusion Drive.

The Update to OSX 10.10.2 (14C81h) helped my out.

Now it is running much smoother. Not perfect, but definitely faster.

Like other users I use the Increase Contrast trick to make the Mac usable for my Web Design work.

When I have contacted Apple Support, they have no record of this issue and told me to re-install the OS. Hardly a viable option considering the Mac is just 2 weeks old! This smacks of the 'bad old days' of Windows where re-installing the OS became a way of life.

I am running Parallels Desktop because I need to use Windows programs. My issue seems to be memory related and using the excellent Memory Clean application, I can see the amount of available free memory. I have the base 8G amount of memory installed. As expected Parallels is quite a memory hog and I can regain nearly 4G after I quit the program. After running Memory Clean, the system is again usable and Launchpad is almost as fliud as it is after a log-out and log-in. Moving between windows is fluid and I can no longer detect any application lag.

I don't see any improvement with 10.10.2 (14C81h).

Me neither, it's placebo. I get the illusion that the system is better when I'm using just a few apps after a reboot, but inevitably, as time passes and more apps are used, the UI comes to a total and unbelievable sluggishness, not only mission control as the thread title suggests, but the whole UI including window dragging / focus, etc. So frustrating.

Although I agree it's ridiculous.. you have to evaluate which apps you have installed especially those that are installed that are in the top bar of the mac. I am on 10.10.1 and have almost no problems now that I have figured out which apps they were. I currently have 5...6.. apps open at a time and mission control is now usable and I have the 2GB GPU. It still lags but not that bad at all and nothing else in the UI lags. I've had the computer on without a restart for over a week now.

I agree it seems there's some relation of the problem with the number of items in the menu bar, I'd figured that out already. I've reduce them to a bare minimum and it seems to help a bit. But still, far from the performance and smoothness I get from my much under specced macbook air running the same OS X version.

Look at this thread (it's about the M295X):

Re: Mission Control performance on 5K Retina iMac

This is very interesting and maybe the reason for the problems, the GPU RAM of the M290X seems to be nearly empty all the time. All other Macs (checked iMac 5K with M295X and iMac 21.5" from 2011 with 1GB GPU RAM) use around 90% all the time.

So it seems to be a driver issue.

I hope it will be fixed soon.

Mine seems to behave when “Default for Display” set for the resolution. Anything higher than that increases the slow animations within the UI. I’m also running that 10.10.2 beta.

The "Default for Display" setting makes no difference for me.

Meanwhile it is slow as 10.0.1 with 10.0.2.

I hope it will be fixed soon. It is an annoying bug, but I decided to live with it and not to change to the 295X.

This is a well documented issue which appears to affect a large number of previous Mac OS's, just search "mac jerky launchpad".
I spent many hours on the phone to Apple support and they have no knowledge if the issue. It seems to just be a Mac "thing" and after many phone calls to Apple support it is clear that they do not see this as a bug. And that is why it still isn't fixed in 10.0..2 beta.

I have just come over from being a Windows user and I do have to chuckle because I could run as many programs as I liked and the graphics never degraded. It would be interesting to get a response from an Apple represemtative...

I found this article and I find the lag to be much less noticeable. The closer to zero the last part of the command is the quicker it'll do animations for Mission Control, or at least in my case. I set mine up with "defaults write com.apple.dock expose-animation-duration -float 0.1" and it seems to be animating like it did on my last iMac. http://osxdaily.com/2012/02/14/speed-up-misson-control-animations-mac-os-x/

The drivers seem to have changed with 10.10.2 (14C81h) compared to 10.10.1.

Before, Cinebench and also the OpenGL Driver Monitor (part of Apple's Developer Tools) showed it as "AMD Radeon R9 M290X OpenGL Engine, Open GL Version: 4.1 ATI-1.28.29" and now its "AMD Radeon HD Prototype OpenGL Engine, OpenGL Version: 4.1 ATI-1.30.4". I don't know how much "Prototype" has to say in this context but it suggests that this is not the final version and that they are still working on it.

The change of the setting to 0.1 made it smoother for me.

It still lags, but not so much as before.

I hope they will fix the driver. Prototype sounds not final 😉

I guess I'll put my 2 cents in on this thread. I'm glad I'm not the only one experiencing this display problem on a three thousand dollar machine. I've had my iMac 5K for about a week now, and my biggest gripe is the lag/stutter when sliding from desktop to desktop. I've got the 3.5Ghz i5 32GB RAM 512 SSD with the M290X graphics card, and I've also got a brand new Thunderbolt Display hooked up to it. I think it's BS if you call Apple and they say they're not aware of the problem. I'm definitely not reinstalling the OS, and from what I've read, it doesn't make sense to return it for one with the M295X graphics card. I've got way too much time invested in setting this new machine up, to do something like that! I guess I'll try some of the many "fixes" on this thread, and see what happens. Hopefully, like what most of the people that really sound like they know what they're talking about, it's a software/driver issue that can and will be fixed soon.