FCEUMM3DS is a quick port (maybe an hour or two) I made of the FCEUMM libretro core to the 3DS, based on my existing Nestopia port. The official RetroArch port to 3DS will likely be better than this, but since I had most of the work already done, I figured I might as well plug the FCEUMM core into my existing work to have something much nicer than Nestopia until the official port is stable and easy to use. The emulator seems to run at near full speed, at least with Super Mario Bros. It isn't quite running at full speed though, which is evident from the choppy sound quality. It's definitely a lot faster than Nestopia was. No Source!