Theres loads that have issues like this guy is asking how to improve one.
Switch n64 emulation is far from pc quality, which even today is not flawless.
I advise the op to kindly listen to me and and this angry guy.
You will find games run nice, loads will run slow, you will need to change cores, settings but please never over clock.
Your putting strain on your console to try make a rom run better that is highly likely going to run like shit regardless.
Ive been part of the emulation scene back in the 90s and these cores are basic ports of pc plugins and dont always port over perfectly, retroarch is a program made to work on multiple devices.
The cores and plugins are all to work within retroarch and each device and hardware can cause issues, they dont make a plugin or core dedicated to just one device.