Alright I think I found the main culprit for my performance drop in 5.3:
I believe I have a greater than expected perf drop from my 5.3 migration because of my particular hardware setup.
My CPU is slightly bottlenecked by my gpu. IN 5.1 THIS CPU GAME THREAD BOTTLENECK WASNT AS BAD AS IT IS IN 5.3. But it appears that in 5.3 im consistently more CPU bound than I am in 5.1. (See pic below of my frame time matching game [cpu] time.)
This is actually relieving to me. If most players don’t have bad CPU bottlenecks on their rigs, their framerates shouldn’t be as low as mine on the same GPU. Also this is nice because I have a lot of power over improving the game thread with better programming (less world ticks). By using Live Session/Trace/Stat file recording I can fix heavy CPU processes and stop the game from being CPU bound.