Since I have no RetroPie in front of me right now...
Activate the statistics. If the Frames are not 50, you have a problem. Delete configs again, edit them manually and start Vice (without messing with configurations via thw GUI)
if they are connected, they are not showing up as input devices and I saw little in dmesg. output of cat /var/log/syslog after they are connected might give more info. (Use an external site for that log - it will be big)
@Rion
still, my point stands. you should have more justification than just 'use my guide instead' on every thread where someone talks about mounting USBs. i don't see how your method makes any difference to OP.
I have been using mupen64plus-rice-hi_res legend of zelda oot. But this has been happening with other emulators in the past. I remembered the way I was able to make changes was by launching a freshly loaded rom (this instance was NBA showtime n64) , never been played on this system before, and access runcommand. Once in there I can change the default emulator. Then I exit the runcommand, and can now change the runcommand settings on the problem rom. I know that seems really confusing. Sorry about that.
@skiddlz, I have to do this every time I update since it adds in Megadrive to the file you edited. Go to that file and delete your old Genesis entry. Find the new Megadrive entry and rename it to Genesis.
I may try what herb fargus is suggesting so I don't have to do this 452 more times.
Is it realted to the limitation of the Raspberry Pi3? Or can it be fixed?
I use a memory split of 320 as advised in one of the retropie setup tutorial.
Does the game really requires so much power that it slows down while lots of explosions/enemies appear on the screen?
From the RGUI menu you can "overclock" the NeoGeo. I did that and it works perfectly. I heard that on the original console it lagged too, it's not really the RPi's fault. Still that game is freaking addictive and one of my favorite arcade games.