Exporting times increased massively

Hello all, New to the forums but have been playing around and using shotcut for a few months. Just recently when I export a video it is taking over 4 hours to export a 40minute video, yet a month ago it was only taking about an hour and a half to 2 hours (sorry can’t be specific).
I’ve kept everything the same but the only thing I have noticed is that my CPU use to be running at 100% but now its around 60% usage. Can anyone shed some light on possible reasons for the time increase/CPU drop?

Shotcut version : 18.08.14

PC specs:
CPU - i7 7700k @ 4.20ghz
Ram : 16gb
Solid state drive used while exporting
Windows 10

shotcut settings:
H.264 high profile
1920*1080 res
progressive scan mode with parallel processing on

If you are using the 32-bit version, this is expected. 32-bit uses less threads to use less memory.