I too have occasional "bogging down" issues if I use IE on my Win 8.1 desktop PC.
I usually use Chrome, with which I have no such problems. However, Chrome doesn't have a proper High Contrast colour scheme. I need this sometimes as I had an eye injury a few years ago and occasionally the glare off a white background makes it a uncomfortable to view anything on the screen. IE works well with Windows yellow on black high contrast scheme.
A bit off thread I know...but Chrome might be worth a try. You can always uninstall it if you don't like it.