Well for one, you didn't actually attach your settings. If I were to take a guess, here are a few settings that have been revamped in some way and could impact performance:

Options -> Configure -> General -> CPU Emulator Engine
Select JIT Recompiler (Recommended)

Options -> Configure -> Audio -> DSP Emulator Engine
Select DSP HLE emulation (fast)

Options -> Graphics -> General -> Backend
Try switching between OpenGL and Direct3D11. Performance varies based on the graphics card, and even somewhat depending on the game.

Options -> Graphics -> Enhancements -> Anti-aliasing
Try switching this to None if it's not already. Anti-aliasing can be really slow.


There's a good chance you're already aware of these options and have tried them. I'm just taking a stab at it because you didn't give much else to go off of. Generally I don't think you should have much trouble with poor framerate, as I have a similar set-up and Dolphin performs very well with Gamecube games. (Haven't really tested a lot of Wii games, but when I did I got pretty good performance out of those as well.)