After many years with Pro Tools HD, this is the first time it has been necessary to use a graphic tool application to make Pro Tools flow.
When I use Apple Quartz Debug and deactivate "beam sync" then it works fine.
Autotune 8.1 in audiosuite is nearly impossible,if not for the Quartz Debug utility.
I think i am one of many customers with graphics issues in PT 12.x But the more we make complaints, the better chances that you will fix it next time.
By the way: The machine is an Apple Mac Pro 5.1; 12 x 3,46GHz; 96GB RAM; Radeon HD 7970 GPU; 2 screens: one 5k and one 2.8k; one Avid HDX PCIe with 16 I/O and several SSD disks.
First I found out, that the mixer-graphics would flow fine, if the Edit window was closed. If I had just a little arrangement with both windows (mix + edit), then graphics would stall (freeze cirka one second) again and again. when I moved faders in the mix window, even though edit window was zoomed all the way out.
So for a while I was working automations with only the mix window open. But when I ran out of patience, I started searching on the issue. And it seemed that a thousand other Pro Tools 12.x users had similar trouble. And they advised the "beam sync" solution.
But it can not be Avids plan to make Pro Tool users dependant on utility tools to make Pro Tools flow, huh?
I am looking forward to get an update, where these issues are gone.
Kind regards from Denmark :)