Freezes (only) in Northend and ICC

I have the problem that the game keeps on freezing every 2 mins and sometimes the game doesnt respond anymore at all.
This only happens in Northend during questing, never happenend once outside of Northend.
And it also happens in ICC 10/25 (only at 4th boss and at Professor Putricide) but never in any other Raids.

I doubt that its a hardware problem, cause nothing is ever close to 100% usage and my PC is fairly new.

Addons i use:
AtlastLoot
Bagnon
Bartender
Cooldowns 1.1.3
DBM
GearScoreLite
Quartz


Any Help would be greatly appreciated