So, when I first run a game in Dolphin, it runs great with barely any lag or anything (Hi, overclocked i7-2600K).
But the problem is, when I stop that game (SMG in this case) and try to run something else, it will run at 0FPS and the VPS and speed counters will jump around, and nothing ever seems to happen.

Is there any way to solve this issue?

"run something else" means closing SMG and opening another Wii game in Dolphin?
I dunno what could cause it. Dolphin can be quite buggy sometimes.

At least you're lucky enough to get full speed. The most I get is 33% on my shiny new laptop

I never run Dolphin on my laptop, since it is a business laptop (Very portable and a REALLY nice battery), which is very bad in graphics and processing.
I run it on my PC at home, which is not very good either, but NSMBW works with _nearly full speed.
But when I conenct Dolphin with a PC controller, the buttons get mixed up. Even if I make the configuration COMPLETELY right, I always press 'UP', even if I dont. Also other buttons cause problems. ;(