Low frames after pre patch

Hallo everyone, i started to multibox with four toons at the end of 2019 and it's very funny.
after the prepatch i have low frame (9/10), while before i havn't those problem (usually i had 30 fps for each toon) and obviously that makes the game unplyable.
i have a i5 7600k as a processor; maybe is it too old for the graphic update of shadowlands/pre patch?
ty very much

Make sure your graphics settings are correct. Prepatches have a tendency to reset them to defaults, so you might have them bumped up to higher than you were using previously. Especially anti-aliasing will absolutely eat your frame rates.