I find IE hogs resources especially if. like me, you leave the PC on for long periods. Does it sort itself out if you close IE completely, then open it anew again ?
I tend to get in a mess enabling and disabling add ons. Never know what I need or if it moans later what to turn back on. Las time I tried that, going back some time ago, I ended up with next to nothing enabled (and IIRC the problem still wasn't totally solved).
Maybe the answer is to try a different browser ?