Exported your test 47:00 file at 1080 Medium Quality H265. GPU average usage was 10%. That resulted in a bitrate of 162Kb. Video acceptable but not high quality. Took about an hour.
A 12hr file seems out of reach for typical PC resources. Especially with H265 encoding at high res. If H265 is a must, consider breaking up the project.
What are the specs of your current unit: CPU/GPU/RAM?
Be sure that the video driver and Direct-X are current. https://www.nchsoftware.com/videopad/kb/1772.html
Suggest MPEG4 encoding. Infinitely faster than H265. At 25000kbps GPU utilization was high and video good. File size: just 1.92GB, bitrate: 5.645 kb/s
Run the 64-bit version of VP if possible.