Frame skipping when enemy is low hp or lots of ults are being used AKA teamfights.

even if they dont use ult or do anything that might stutter it always happens when they are low hp and during team fights. now why is that? this is a brand new laptop man! i bought a new one because the old one cant run skyrim well, that old one can run lol very well with no stutter! bad fps but no unfair low hp stutter.