I gave updating from IE9 to IE11 a try too. With IE9 my svchost.exe is usually around 45 MB after 3 weeks, which isn't too bad. I'm not sure if it's a fluke yet but after 7 days of uptime with IE11 my svchost.exe is at 29 MB. That's a pretty huge improvement considering how high it would get really fast before. I still have 2 new IE11 updates to get, which I'm worried they will make it worse or restarting my computer alone will just make it go back to the way it was.
Edit:
Nevermind. It seems talking about it reminded it that it's broken. A few hours after I posted this it just started increasing really fast. It was very odd that it increased slowly for 7 days though.