Really, SDL_GetTicks returns 32bit msecs using 64bit usecs of timer_us_gettime64 function. i have tried a couple of fixes but not work. Maybe timer_us_gettime64 implementation have overflow, for example only use 48bit of 64bit for any reason.
Back to NEO4ALL/AES; yesterday night i have tried Metal Slug X with prefetching and works ok but it run not full speed because neogeo memory switching is secure mode (get_context->modify->set_context) ... We have to speed up this operation using direct access to FAME memory table .... I NEED YOU FOX !
Also, i have tried Art of Fight 1 (16MB rom) and works very very fine, i remember that AOF1 not works with NEO4ALL/CD.