I believe the scrolling issues are tied to their use of position: fixed for the sidebar where that DIV has its own internally scrollable frame via overflow: scr

I believe the scrolling issues are tied to their use of position: fixed for the sidebar where that DIV has its own internally scrollable frame via overflow: scroll. The combination of those two are taxing on the browser's overall layout system which causes a dramatic slowdown on less powerful machines. Heck, it's even a little sluggish on my iMac.