There's definitely different variations of it then. Ambient has a very noticeable effect for me, and limiting FPS does nothing. Once broken it used to stay broken, but unmuting ambient makes it recover like whatever's getting bogged down starts clearing up after the spell spam stops enough. It's like there's a meter that fills up and past a certain point starts distorting, and recovers when there's less going on, but some areas just do it even without any spells at all.
If wonder if different types are based on what CPU people have, but that sounds like a lot of work to gather the info. For reference:
SYSTEM_CPU AMD FX(tm)-8350 Eight-Core Processor (8 CPUs), ~4.0GHz
SYSTEM_CORE_NUM SYSTEM_CORE_LOGIC 8 SYSTEM_CORE_PHYSICS 4
GPU: AMD Radeon R9 270x
RAM: 16gb DDR3
Edit: To be clear, when I said CPU power I meant this option:
https://i.ibb.co/X5cQJV2/cpu.png (Most people probably have it at 100% already unless they're on power saver or on a laptop.)