I previously posted in the bugs forum and I was pointed in the direction of the support section. I tried repairing the game but that has not changed anything.
The issue is that, particularly recently, when I log in and begin playing, I get a sudden catastrophic drop in performance. I checked my task manager and discovered this:

It happens more often when I first enter Cyrodiil. It doesn't happen all the time, but when it does, I am forced to quit the game and restart to 'reset' the memory usage. Usually, the memory usage of ESO starts at 2000 MB and slowly creeps up to 4000+ if I stay in the same zone. My computer simply can't cope with a sudden ramp up to over 12,000 MB though. Does anyone know how I can prevent this?