Looking at the 1.7.2 release page, there is one more possible trick to get a performance boost on the slower systems.
Instead of sampling audio from the last frame, sample it from the first frame, then use Hard Disable Audio for the subsequent frames. If I can get clean audio with 0 frame runahead for Genesis Plus GX, I’ll probably reinstate the hard audio disable patches.
Adding hard_audio_disable and changing runahead to only output audio on the first frame appears to be a 10% speedup.
This would boost Genesis Plus GX on the PS3 from 51FPS to about 57FPS, but that’s still not quite 60FPS.
One other possible optimization would be to not invalidate the tile caches on load state, making it check which bytes have changes and only invaliding those that have changed.
Edit once again:
Got it working! But I have no idea how fast it would run on a PS3 at this point. Probably easily more than 60FPS at this point.