Just to add my own experience with it... I have noticed just once that the scroll speed got "laggy" when scrolling through heavily colored text (a bunch of testing I was doing for a script that had a lot of colors on each line and filled almost a full maximized window). As soon as I got beyond that, it went back to normal, but every time I went over that area, it got noticeably slow. I've never noticed that happen before, but wanted to put out the info about lots of color changes being a factor.
yeah, noticed this too when text is larger/colored, its ALOT more laggy, really strange bug anyway since my old laptop is a crap amd on xp and has no problem with it on 32pt text even lol
if any1 finds a fix for this plz post here, for now i am using irssi, and its ugly!