I have been trying latest RetroArch + PCSX_ReARMed core on 32bit ARM (Raspberry PI3b+), and most games run well, but then there is “Bust A Groove”, the well known dancing classic that relies on precise input timing: its totally unplayable since it (almost) never registers input in time. In other games, I can not see much input lag: I can even enable max_swapchain=2 on the Pi3b+, but it does not do much for “Bust A Groove”, and my TVs “game mode” is enabled. So I was wondering if the cause for this could be PCSX_ReARMed “inaccuracy” regarding internal system timings instead of “external” input lag (RetroArch, TV, input…).
Have you tried Bust A Groove on PCSX_ReARMed? It seems to be an otherwise good core, and 3D renderer based on NEON is specially spectacular because of its fidelity to PSX GTE results. Is the game playable on the Beetle_PSX core? (I have no machine capable of running that well for now).