Update: I've attempted to run the application as an administrator which seemed to cache to D: for the preview, but faced another error when rendering.

I am having issues changing the Cache folder. I've gone into Edit > Preferences > Performance and have changed the Cache folder to a location in my D drive, however it seems to still be using the C drive for caching, even after restarting both the application and the computer:

https://i.imgur.com ...

So I've enabled OpenCL hardware acceleration via Edit > Preferences > Performance, yet whenever I render an image, it seems to be using the CPU almost entirely, with no GPU help whatsoever:

https://i.imgur.com/Fen1UOW.png

Is there something I'm missing? I'd like the GPU to be responsible for ...