reinstall - not worked
it looks like you sequence runs heavy on Ae. Try caching the frames and then play them. Is it 13.8.1? What Os version?
You are looking at the footage panel. You showed us Live Update option selected for the Timeline. There is no setting or option for live update for the footage panel. The footage panel must cache before you can quickly scrub through the footage. This is normal. It's always been this way.
I tested on the most basic sequents (2-5mb). The problem is not in the settings seem to conflict with something.
2 PC (Win 7):
1# version AE - 22.214.171.124
2# version AE - 126.96.36.199
(intel i7-6700, 16Gb RAM, nvidia GTX 970)
1. Go to preferences- disk & media cache and clear all the cache (both)
2. Reset your Ae preferences
1. 2. - did not help
i now reinstalling AE, clear registry - working!!!
Great. Thanks for sharing what solved it.