Disabled FoxyTunes add-on and now opening a new MSIE tab is quick.
To fix this, open MSIE, then go to TOOLS >> MANAGE ADD-ONS.
Select FOXY TUNES and disable it. Voila, 4+ seconds of your life returned to you each time you open a tab.
I still prefer FireFox by a couple of orders of magnitude but YouTube is still flaky for me.