Its very unfair to compare the projects for two main reasons imo. But i’m obviously biased ;D
From a technical standpoint, the two emulators face very different challenges. The 3ds GPU had to be completely reverse engineered as it is an unknown chip (PICA200) from a relatively unknown graphics company. The shaders used by the PICA support several operations that frankly do not map well to desktop graphics cards, meaning citra has been computing a large majority of the graphics pipeline on the CPU, which is slow. Moving whole graphics pipeline to run on the host GPU is proving to be very challenging, but still possible (so when that happens expect a big speed up for people with graphics cards in their computers). The wii u on the other hand has a custom card made by AMD, and it doesn’t have all the same challenges that citra faces. In fact, the open source wii u emulator, decaf, has had a mostly functional openGL backend for a long time now, which lends a lil’ credibility to the statement that a wii u gpu is easier to emulate on desktop graphics cards than the mobile gpu used in citra.
Secondly, having 20 developers doesn’t mean much… they hardly work on the project anyway. Heres the top 20 developers: https://github.com/citra-emu/citra/graphs/contributors and heres how many of them contributed anything last 2 months. https://github.com/citra-emu/citra/graphs/contributors?from=2017-11-12&to=2018-01-13&type=c So roughly 5-6 of the top contributors did anything, and most of the changes affect absolutely nothing a user would care about. Most changes are like that though
Anyway, since its unpaid, no one is forced to work on anything, and no one is forced to make citra faster. This is a key point as CEMU lives and dies on how fast its running. If they stopped making it faster, then people will say “dead project” and stop donating. If they stop donating, then, like a self fulfilling prophesy, it really will become a dead project, so they work very hard on speed. Citra doesn’t have this problem, since theres no money in the project, theres no requirement to make it fast. (Side note: we do like making it fast, but we aren’t obligated to. We do make sure to prevent it from getting slow though) What little donations and ad revenue citra gets goes to paying for web hosting and supporting things like the multiplayer servers we host as well.
If you ask me why i’m not making it fast, i am n00b and trying, but its hard I’ve started on hardware texture en/decoding which should give a good speed boost to several games, but as I said, i’ve got a lot to learn before its finished. (my contributions have mostly been in smaller projects like i made the gui for multiplayer, and i made screen layouts, and mingw builds, and hle swkbd and stuff)