Windows 10 + SWTOR OS slowing down issue

Alright so I upgraded to W10, and I'm loving it so far. Everything works perfectly well for me.

Except for one thing.

SWTOR runs excellent on Ultra graphics, steady 50-60fps and all. But everything else just... doesn't function at all when playing SWTOR? I have two screens, and I multitask a lot when gaming. But when I play SWTOReverything outside the game slows down a lot, to the point where it can take up until one minute before the message I'm writing in steam (for example) shows up and is sent.

Strangely enough, SWTOR doesn't take up much CPU or Memory usage at all on my computer, while ESO (Elder Scrolls Online) for example takes almot double the amount yet I don't have this issue here.

Does anyone have any ideas on what might be going on? It only occurs with SWTOR :(