Comment by dustbunny
Theres some missing information here. A "rollback that doesn't do anything" shouldn't be noticeable to the user. It would only be noticeable if the game simulation can't keep up with the # of frames it's being asked to simulate. And in street fighter, the simulation is ridiculously simple. There should be no reason why street fighter wouldn't be able to "rollback and resimulate" dozens if not hundreds of times per frame. There's no way that game is CPU bound... Am I missing something?
I think you are underestimating the per frame computation cost or massively overestimating the base model PS4. Remember that all fighting games have to lock 60fps, 16ms is not a ton of time for the handoff from input interpreter (SF has to parse backwards over the past several frames to see if a forward input is completing a quarter circle, double quarter circle, dash, etc) > game state update tick > graphical and sfx update pipeline. The issue with clock syncing meant that the worse your machine was, the more your opponent would roll back and the bigger the rollback windows would be because every single frame of your inputs would come late.
Here's an example of the constant one sided rollback: https://www.youtube.com/watch?v=aSB_JlJK_Ks
and an example of how players were aware that mashing caused frequent rollbacks: https://youtu.be/_jpg-ZiE70c?t=105
Eventually PC players learned that they could "fix" this by alt-tabbing out of the game, taking away dedicated GPU processing so they could be the peer that was falling behind.