UI panels flickering when using brush tool, shift key, ALT key.

Hi. 

Ever since upgrading from CS6 to brand new PS on a new computer I'm having lots of issues (new PC is high end, runs perfectly so I know it's not the computer causing this problem).

The main issue is the UI/ Toolbars and Navigator panels flickering when using the application, mostly when using the SHIFT keys and the brush tool (I'm a digital painter so need to use these for my workflow all the time). 

It's almost like the active file window is trying to push itself on top of the panels that I just mentioned when using these keys. I've tried turning off the Graphics Processor and that made PS unasable (stuttering and jagged scrolling). I've also tried using the different settings for the Drawing Mode for this too, nothing changed. 

It also is not the same flickering issue that other people seem to have with the whole screen flashing black and white. 

Sorry to sound like a Karen but this isn't really acceptable when I'm now forced to pay a monthly subscription, CS6 ran perfectly and I wish I could use that again, but that's now not possible. Any help would be appreciated. 

Thanks.