I just updated to 8.3. I do not have the problem you state with 7 tabs open.
Hitting the tab switcher opens the tabs and it responds to touch immediately. No stuttering, nor delay.
I have seven tabs open now. I noticed a *slight* stutter when it animated to show all the tabs. Barely noticeable. But it didn't do it again after the first time. Is this what you mean?
We have like 100 threads about 8.3 and bug fixes. Can't this question be asked there? Do we really need a new thread for every single bug that someone has/had?