Well, huge resolution? Multiple comp views? I could well imagine some hardware acceleration issues, but without exact system info it's impossible to judge.
Sorry about that, I didn't know if system info was important as everything's been running fine up until a week or so ago, I was just hoping it was a bug someone else had experienced that may have had an easy fix.
It's not a top of the range PC, it's a couple years old but never given me any grief. This is the 2nd time I'm editing this project, due to a deadline needing to be met when it was originally shot, I'm now re-editing the effects because I no longer have a deadline (it was originally a film school project), so the only way it would be a hardware is if the hardware was faulty, because the last time I edited the project, I didn't have this issue. But if it was a hardware issue - like my graphics card - I figured I would be having problems or experiencing bugs with other programs as well.... But this is literally the only odd thing that's happening on my computer at the moment. As far as I can tell, everything else is running completely as it should be.
The screen resolutions are 1080p on two 32"monitors (one connected by HDMI, the other by VGA), the footage I'm working with is 4K Pro Res, but the project is 2K. Shot on a Sony a7s with a Atomos Shogun Recorder (don't know if it's relevant, but trying to give as much detail about my system and project as possible).
Processor: AMD A10 6700 Quad Core 3.70ghz
Graphics Card: AMD Radeon HD 8570 2GB
RAM: 16GB DDR3
System: Windows 10 Home
2TB internal HDD with 3x4TB externals connected via USB3.0
Let me know if I missed anything out or you need anymore info. Thanks