Rendering MP4 on Pc and using on Mac

I edit on my Macbook with FCP, but I want to render the .insv files on my PC because it is brand new and can process the files much faster. I'm havng an issue where files rendered on the PC play perfect on the PC, but on the Macbook the video comes out choppy and the audio is clear. The fils are also much larger on the PC, double. I went into prefferencs on the PC and tried differenct combinations of the exporter codedc and that made my files almost the same size, but I had the same play back issue. There are now issues when process and playing on my Macbook alone. PC has high specs at i9, 32 GB ram, GTX 1080ti

I thought that it being a mp4 it would play the same on either device. What setting am I missing?

Is it even possible to do what I'm attempting?