Recently I have been encountering extreme amounts of stuttering in the game, where my game would freeze for 3+ seconds at a time constantly throughout the raid. I have struggled for days trying to find a solution but I have finally found what my issue was. I hope I can help at least one other person.
The main issue I was having involved the Windows Page File. The Page File is a portion of one of your drives that gets used as memory when there is no more available RAM left on the system. Usually windows handles this fine but in my case I have 2 SSD's and a HDD. For some reason, Windows has been using a portion of my HDD instead of one of my SSD's. This was causing my game to hitch and stutter because my HDD is obviously not nearly as fast as my SSD's are and for that reason, the game / my PC was waiting on my HDD to catch up. You can test if this is your issue by monitoring your drive performance in the Task Manager. Whenever I would get a stutter, my drive usage would spike to 100% then quickly go down, repeatedly.
Press the windows key
Type “SystemPropertiesAdvanced” and press enter. Run as Admin if prompted.
Under Performance, click Settings
Click Advanced at the top
Under virtual memory, click Change
Uncheck the box at the top that says "Automatically manage paging file size for all drives".
Now you will be able to view which drive is acting as a page file. If you have an SSD and the Page File is acting on your HDD, change the page file drive to an SSD.