On a recent Pro Tools Expert podcast we were asked what version of Mac OS X we recommended for our Pro Tools computer. The team gave various answers which included Yosemite and El Capitan, but when some of the team were quizzed about why we could not recommend El Capitan the issue of the laggy video performance was raised as one reason for not recommending it.

For those Pro Tools users not aware of what we mean by this, watch the video below playing an identical part of a Pro Tools session, one on Yosemite and the other on El Capitan.

As you can see the meters on the session running on El Capitan are not smooth but jerky. What makes matters worse is that some Pro Tools users are having no such issue whilst other users are tearing their hair out, as you would expect.

The problem can be further exasperated when using certain plugins, which make the problem even worse. However this issue can also affect some people running Yosemite, but on the whole El Capitan is for some the real show stopper.

Why Is This Happening?

We reached out to some plugin developers to ask for their input on this issue, here are their replies;

"Looks like you are hitting the 'known' El Capitan slow UI issues.  Apparently Apple has decided to change how they queue up the refreshing of user interfaces in El Capitan - it affects MANY manufacturers"

And this one;

"the UI sluggishness you are experiencing is a known issue related to El Capitan specifically. We've spoken with Avid and they are currently working on fixes for the Pro Tools app itself, as well as researching what type of optimisations they can recommend that we implement in our plugins. (Some of Avid's own core plugins, such as "Click II", also continue to demonstrate the problem to a rather severe extent). In the most recent release of Pro Tools (12.5.0), Avid says they have "Fixed a set of severe UI sluggishness cases when using OS X El Capitan"; although in my tests I have not yet seen a major improvement in performance."

And finally this one;

"This may be related to changes that Apple actually made in Yosemite.  Being Apple, they didn’t say a word about it—we had to find out the hard way. Here’s a brief explanation.  There’s a period in the life of an application when it’s given a chance to repaint anything that’s changed.  OS X used to be fairly generous about this, but they really tightened up the time window in Yosemite.  If things didn’t get finished, OSX just cut them off.  This caused some elements of my GUIs to flash and flicker, especially at larger sizes.  My solution was to do the hard work of redrawing in the context of the UI thread(s), not in the context of the actual screen update. This means that the screen update for me is just a series of BLTs (Block Transfer) of already-painted elements. This refactoring of the UI occupied quite a large amount of my time last year."

Fixes For Pro Tools 12 Screen UI Redraw Issues

Pro Tools Users Running Yosemite

If you are using Yosemite for Pro Tools and think you have a laggy display then you can download the free BeamSyncController app which disables and enables Beamsync in Yosemite. We have tried it and see a marked improvement.

Go here to download BeamSyncController and follow the instructions carefully. Please note this is a third party solution and we take no responsibility for it's suitability or offer any warranty, this is simply a link for you to use and to decide if you wish to use it.

Pro Tools Users Running El Capitan

There is no simple fix for El Capitan at the moment because it uses "Metal" not "BeamSync". Some users have reported moderate improvements by adjusting some of the Accessibility options in the Preferences pane, we've not been as lucky.

Some Pro Tools users have found improvements with Pro Tools 12.5 whilst others have seen better results using Pro Tools 12.4 - there is no one-size-fits all solution so it seems.

The only solution is to back up your entire Mac and reinstall Yosemite.

Summary

If you are a Mac user and are currently using OS X Yosemite then we strongly advise to stick with that version of OS X until these issues have been ironed out.

If you've managed to find a fix for this issue then please let us know.