iMac 5K Retina extremely slow Mission Control

so if i understand you correctly, there are no longer any Mission Control GUI lags on your iMac, it works as expected, completely smooth transitions?

Good News!

Looks like the 10.10.3 update has fixed the lag issue, at least for me! Been running it for about an hour now, and no lag whatsoever!

Thanks,

- Scott -

Yes the problem is solved for me too, but there's a new biggest problem with an external display ... https://discussions.apple.com/thread/6983326😢

Yikes. It's like they don't test this stuff...

My 24" display is just fine, so far. Keeping my fingers crossed (is there a new emoji for that?)

- Scott -

I wish... it is significantly better for me, but still not 100%. I can see a difference still with contrast & reduced transparency on (being smoother). It may get worse (as it did before) but I can't really say without running it for more time.

Disappointed.

Good News!

Looks like the 10.10.3 update has fixed the lag issue, at least for me as well.

I will note it is faster with the contrast fix turned off, but nearly as fast with the fix still applied.

Yes, can confirm it's a lot faster with Reduce Transparency enabled. Once you disable that option, mine got a lot slower, and then when re-enabled, could never quite recover. While not ideal, I've been running w/Reduce Transparency enabled for a while now and have gotten used to it, so it's good enough. But I agree - it should be addressed with the both options.

- Scott -

i'm still seeing the annoying Mission Control lags on my late-2009 iMac. it used to work just fine, with smooth transitions, before upgrading to Yosemite. so it's back to Mavericks for me, as i need Mission Control to work properly.

Still the same problem after updating to 10.10.3

Only the option "increase contrast" works.

I see no difference after upgrading to 10.10.3.

Mission Control lag exists exactly how it did on previous OS versions on my Late 2014 Retina 5K (w/ 4GHz processor and 16GB of RAM.)

There obviously have been a LOT of replies to this thread since 10.10.3. I'm sorry, but this problem has NOT been fixed in any manner. Sure, it works great for a little while, but after a few hours and more than 5 or 6 programs running, it's right back to a constant LAG. If I restart my 5K iMac with 32GB RAM (3.5GHz processor), Mission Control is awesome. No lag at all. Give it a few hours and a few more programs running for awhile, and it's awful. I'm pretty sure we just have to live with this. It's not getting fixed in my book. That's MY 2 cents, anyway.

Yes you're right... the problem is back after few hours... 😕

Unfortunately it is now the same for me - it obviously wasn't fixed in this release.

A while back I opened a bug report for this and the response back from Apple was:

19915387 iMac 5K Retina Mission Control Extremely Slow

State: Closed Product:

Rank: No Value

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Duplicate of 18007478 (Open/Closed)

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Does anyone know if 18007478 is still open? That is, are Apple still working on fixing this? (Not wanting to presume anything...)

Cheers, Kent

i hope Apple fixes Mission Control soon. It's annoyingly unusable in its current state.

here's an example of what Mission Control looks like in Yosemite. notice the jerky transitions when MC is activated. quite unpleasant.