Humm je n'ai pas le souvenir de "ralentissements" sur mon pi2. Tu peux essayer de modifier le core utilisé pour l'émulation gba. Sous ES, Menu Option / Options Jeux / Options Avancées / GBA / Emulateur = Libretro / Core = GPSP etc...
Same problem with Harmony of dissonance, I hope this issue can be solved in Recalbox 4.1 because two months ago I was a RetroPie user and I had not that issue with those games under mgba, greetings from México.
Hi, first, i got my soms from edit no download links at first try pokemon ruby ,saphire ,emerald dit niot work at all. then i found out if you start any GBA game perhaps ruby and befor it runs you press very fast the "+" and "B" key this wil take you to a menu where you select an Emulator and select GPSP!! it wil run but the controls are messed up so i recomend watching this video https://www.youtube.com/watch?v=eM9BB9v9288