Went into the BIOS, didn't see anything that looked like 4G decoding or Extended Address Space, but there were some additional options I turned on. It didn't fix the issue. I've enabled "CSM Support" which from what I can see is the only Legacy boot options I have. If it wasn't clear from the diagnostics, i'm using https://www.asrock.com/mb/intel/h110m-hdv/
Thanks again