Media Encoder Performing Much Better on Bootcamp than Mac OS

I have a file that is 45:00 long and GPU intensive. I am scaling down 2 inputs - 1 is 4k and 1 is 1080p60 - and keyframing the 4k footage to fill in a couple of 'PIP' alpha windows on a plain black overlay graphic. Media Encoder on the Bootcamp side of my mac thinks it can get the encode done in an hour but when I queue up the same file on the mac side it estimates that it will take just over 2 hours. What could be causing the app on the mac os side to be struggling?

Specs:

Processor - 2.6 GHz Intel Core i7

Memory - 12 GB 2400 MHz DDR4

GPU - Radeon Pro Vega 16 4080 MB, Intel UHD Graphics 630 1536 MB

AME version (on both mac os and bootcamp): 13.0.2