There's also someone that build the cores with an old and modified retroarch(so less ram). But I won't promote it anymore since he uploads modified cores without providing source code. I asked him nicely twice in the forum and still no answer...Well, maybe he doesn't recieve alerts. Do you hear me
@SuperrSonic ?
I hear you, I only saw you ask once though. I feel like I already said I was using version 2 of your modified neogeo core with vm because the later versions were not saving bios settings or something (I realize that this is no longer the case.) I just moved the location for the .fs files because it was saving them to the root.
Most of the cores modified are simple changes, usually to get it to compile on older RA, or in mGBA's case reduce the audio samples to get it somewhat to the standalone's speed. Recently I've been looking at cores with huge max_height/max_width sizes,
Nestopia for example has this problem and it would make filters really slow. This breaks the built-in filters somewhat. Genesis Plus GX used to have this issue
but has been fixed recently. I can't think of anything else, the nes cores have extra palettes, and gambatte has the VC palettes because it seems like an obvious thing to do.
There are around 50 cores and it's not easy to maintain them, that's why I keep old versions instead of updating them every time they make a small change. If there's a specific core you say I modified and didn't provide the changes please tell me and I will post it.
There's a special case, where I compile differently some cores: cannonball is compiled with simple motion controls. Pokemini, Handy, and Wonderswan cores are compiled with different video settings to prevent screen tearing because vsync is not available. FCE and all the PCE cores are compiled with 5 player support. These settings are found here:
https://github.com/SuperrSonic/RA-SS/blob/master/Makefile.griffin#L12
If you're working on improving RA might I suggest
https://github.com/libretro/RetroArch/commit/54335ee4969de926058bfd4112a3f68aaec46c98 ever since this commit, RA has become unstable with the number of times games are loaded, maybe you could try looking at netux79's RA which supports pointing and automatic resolution switching, based on a version before the commit I mentioned, so it's crash free in that regard, it also takes a lot less space than my builds too. The last time I tested official RA a few weeks ago, toggling the bilinear filter setting a few times hard crashed the Wii so I must assume it's now restarting the video driver each time. In my builds it always crashes on the 17th game load so I just added a counter that exists on the 16th load.