I’m afraid to say that Guy7001 and I have exactly the same continuing problem (2 seconds smooth play - 0.5 secs pause - then repeated ). Since my last post I resorted to contact with Zendesk. An excellent response in terms of reply speed, etc but to date there has not been a proposed solution which corrects the problem. As suggested I reinstalled the graphics driver (GTX1060, 3 Gb) - no success. I ensured that the graphics card was working on default settings, i.e. not overclocked - no luck. I refused the suggestion that a different card may help - no chance at those prices. I deleted the manual and rolling caches - but no luck. Support said “We are working hard on potential fixes for these previously reported issues, and hope a fix for the issue is coming in one of our latest updates. GTX driver updates could fix the issue as well when they come along.” That is no real consolation to those of us who want to use what we have paid for, with the right performance. I must repeat that the system worked fine, wonderfully smoothly, until one day it didn’t and has not done since.
I’ve never had a £60 application which is potentially so bug-ridden, at least in my (and Guy7001’s) case.
My next step is to do a complete reinstall of the whole system - all 10 DVDs worth + all the subsequent updates. Could take some time. Then I’ll test and report back with good news - I hope.