I'm already way past these limits and no sign of slowdown or soft-capping.
Lovely game.
EDIT: I spoke too soon. Game became unplayable for me after prestige 8. Was at maybe planet 28 before prestiging then planet 1 was unplayable. That suggests maybe an issue with very small values because planet 1 will be tiny at that point.
I see someone else got to planet 33+, which implies the rendering of planet 1 is system dependent. Changing browser zoom magnification or display resolution didn't make a difference on my system.
Until save is implemented, no point in reloading the game to see if reload makes a difference.