This fix assumes that a game which is playable is better than a game which is not playable. Fix: Undo all the "improvements" that were implemented before all the hitching started. Maybe a system restore to 8/1/14 or so.
Hitching started after Valkyrie patch, but someone found a solution here: https://forums.station.sony.com/ps2...emporary-solution-but-frame-rate-drop.204207/