Q: Zoom (Accessibility feature) is extremely slow with multiple monitors [OSX 10.10]

Can confirm this too: 10.10.1 did NOT resolve the issue.

back to square one zoom is not responding and very laggy with 10.10.1

I must have unplugged monitor and it temporarily fixed it

I have this too. *****.

Same problem here

Apple OS X 10.10.1

MacBook Pro (Retina, 15-inch, Late 2013)

Intel Iris Pro 1536 MB

External Apple Thunderbolt display

Yosemite became unusable for me with multiple external monitors and also the overall performance is terrible. I had to revert back to Mavericks! Now life is much better however with my iCloud upgraded to Yosemite I'm sort of stuck!

Apple really did a crappy job on QA for Yosemite and iOS 8, my iPhone behaves really buggy sometimes and the Yosemite is just catastrophic!

Hi I would like to point out that this issue is NOT ONLY related to EXTERNAL MONITORS.

I am running

OSX Yosemite 10.10

MacBook Pro Retina 15" late 2013

2.3GHz 8 core i7

16GB 1600Mhz DDR3

Intel Iris Pro 1536MB

1TB SSD

and NO External Monitors, and the zoom brings the system to a stand still.

There does not seem to be any specific app running in the background that causes this, nor does changing monitor res or profiles, its simply OS X 10.10

System ran like a dream before the update.

Really need this fixed asap.

There is the same problem on an imac mid 2011.

Mac os 10.9 no such problems.

Fix please as soon as possible

Just updated OS X with the latest updates, and so far the Zoom issue on my laptop appears to be resolved.

I hold judgement until I have used it for a few days, but so far, its looking positive...no lag, nice and fast again, fingers crossed it continues.!

There is overall sluggish behaviour when connecting external monitors on macs now, ever since Yosemite. I guess Apple really messed up multiple display feature.. something that they were soo proud about during Mavericks release.

I had the same problem.

Enable "Reduce transparency" it dramatically improves the performance of the OS. Also zoom.

I have the same issue with the lag, but interestingly it seems to matter how many windows are open (even if they are not visible).

10 browser windows open = super slow zooming for me. (As opposed to being smooth in Mavericks.)

No windows open = zoom is still choppy, but not as bad.

Of course this still makes it unusable since normally I'll have several applications open.

Disabling 'Smooth Images' on 'System Preferences' > 'Accessibility' solved the issue for me; surely it was disabled before upgrade! Apple developers should try to be a little less sloppy given there are only a handful of systems they need to test their s/w on--the option should be disabled by default if their flagship laptop graphics cannot interpolate on-the-fly at such resolution.

this did nothing for me. 'Smooth Images' was enabled before also. otherwise everything looks atrocious.

It's all some coding error. I mentioned before in a previous comment that I have 2 monitors. If i have my Windows Virtual Machine fullscreened on my main monitor then all zoom features on both the main and second display run smooth as butter but only if i have the VM on fullsscreen. It wont work if the VM is just maximized.

Same here. Toggling neither 'Smooth Images', nor 'Reduce Transparency' made any changes for me.

I have the same issue on my 2014 Macbook Air, but responsiveness is horrendous to the point of making my mac unusable for about a minute until I can fully zoom back to normal. No difference toggling 'Smooth Images' 'Reduce Transparency' or disconnecting from the external monitor.

I noticed however that reducing the number of open applications improves the frame rate a little bit (but not to the point of being usable).

Also I have another 2012 Macbook Air which I also upgraded to Yosemite 10.10.1, and it does not have that Zoom issue at all, even though it has a lot less RAM.  Interesting bug... Apple should definitely fix.