surely it wouldn't take that long right?
Apparently, it does.
the video I want to render won't render in 1920x1080 resolution
Why not? What exactly happens when you try?
Something in your rig is not functioning as you expect, and I think the best answer would be to get Bill Gehrke involved and his ppbm testing. It's a short process that can give you direct answers as to how each of your subsystems actually functions with a Prpro project.
Thank you Neil
My Premiere Pro BenchMark (PPBM) uses Premiere Pro to test your hardware setup, there are tests for disk, CPU, and GPU. Run those four timeline exports from Premiere and the Speccy tool and submit them and I will get back to you with my constructive comment and suggestions