First you're gonna wanna see if it happens without the HD pack. Some of the maps are pretty big.
It is worth noting that I've noticed stutter/fps drops occasionally even without HD textures sometimes in the map screen.
For settings, I would recommend using only IR scaling and not using Anti-aliasing if you're having FPS issues.. Dolphin has historically done better FPS-wise with IR over AA. Higher IR will basically do the same thing as AA depending on your IR settings and your monitor resolution.
It is worth noting that I've noticed stutter/fps drops occasionally even without HD textures sometimes in the map screen.
For settings, I would recommend using only IR scaling and not using Anti-aliasing if you're having FPS issues.. Dolphin has historically done better FPS-wise with IR over AA. Higher IR will basically do the same thing as AA depending on your IR settings and your monitor resolution.