many 2019version became lag on saving script changes.

This a BigBigBigBigBigBigBigBigBigBigBigBigBigBig problem after I start to use 2019.2.
I've always keeping up on upgrade and now on unity 2019.4
I found most editor's 2019 series got a serious problem which never happens on early version.
That is:
SAVE VERY LAG ON SCRIPT CHANGE!!
(on vs)When you add a blank or delete a word, press ctrl+s.
switch back to editor.The saving circle appears and the editor keeping stuck for 2-4 seconds.
THIS IS NOT A LITTLE THING.!
if you want to add a public variable and quickly switch back to assign it.Each time you would wait.
THIS BUG MAKE YOU CAN NOT WORK!

but I found not al the verion of 2019 got that serious. Like 2019.2.
Some time this problem happens but you could fix it by close the vs editor and reopen.

THIS IS 100 PERCENT NOTHING RELATED WITH system and hardward.
I've already reinstall several version of win10 but same problem happens.
The hardware is surely strong enough to compile just with a flash and this should not take seconds.

I dont know why search on google no one have this problem.
I'd like unity team could take a survery into this problem
Thanks.