VST Performance effected heavily by 2nd screen

Cubase 9
OS 10.12
mid-2012 Macbook Pro (16 gigs of RAM)
2nd monitor: Samsung B2230

Since updating from Cubase 7.5 to 9 three difficult weeks ago, I have been experiencing a handful of issues. But one of the most alarming is COMPLETE FREEZING. VST Performance suddenly spikes, audio momentarily skips, and – if I don’t hit spacebar immediately – the everything freezes: mouse dies, keyboard ineffective, force quit ineffective. I have no choice but to hold down the power button.

Being as one of my other C9 issues involves my 2nd monitor (mouse not behaving correctly on 2nd monitor – ONLY IN CUBASE9!), it occurred to me that perhaps my monitor is effecting this issue as well. Indeed, if I disconnect the monitor, the VST Performance doesn’t spike, and Cubase doesn’t freeze.

A tech at Steinberg wondered if my GPU was failing, but multiple hardware systems tests have found no issue. Not surprising: as I have no other issues w. graphics or performance in any other program but C9, including C7.5, and some fairly hefty editing in Final Cut. No drivers exist for the monitor, in case you were wondering. The issue seems almost certainly C9-related.


Have you tried another GPU? Until you rule it out… for sure! there’s no real moving forward.

How would I try another GPU?

And again, everything was running smoothly in 7.5, and continues to run smoothly in all other applications on the computer.