Almost all Wii and GameCube games have a fixed framerate and have their logic tied to that framerate so if the framerate goes higher, the speed of everything else goes higher, too. However, by modifying the game (usually via Action Replay or Gecko codes) someone might be able to change the relationship between game speed and framerate. If they're lucky, the game will have one single memory location which holds the target framerate or the target frametime and doubling or halving the value held there will make it work at 120 FPS once Dolphins framelimiter is set to 120 (or everything will be at half speed). Usually, though, there are a zillion values which would need to be changed, or, even worse, there will be effects or gameplay mechanics where something takes a fixed number of frames to complete, so games vary from a nuisance to impossible to make a patch for.
Off the top of my head, I don't remember if Mario Kart has a 120 FPS code.
Off the top of my head, I don't remember if Mario Kart has a 120 FPS code.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56