Code is stable on Mac but not Windows


I am trying to solve variations of Navier Stokes for a project. I recently decided to buy a new windows computer (before that, I’ve been working mainly with Mac OS). However, running on Windows the same code (written on Jupyter notebook) that was working on Mac has been giving me issues. For instance, while my fully-implicit solver is stable for small mesh sizes on my Mac, for Windows it becomes unstable for the same mesh sizes.

Is there a discrepancy I should be aware of when making the transition from Mac to Windows? Or what should I do to fix this issue?

Thank you very much in advance!

P.S. My Mac is 8gb ram and my PC 32gb ram