Wither lag

Anytime I go a summon a wither I can’t even hit it because it slows the game FPS so much that it doesn’t register a hit  and if I do get a Hit it wither crashes the game or freezes the game for about a minute  I don’t know if it’s because I’m eating enchanted Apple also and that slows it up so I try to not use apples but I die like the second I see the wither because it hits me faster then I able to move the camera to see it