I think I have the same problem, especially with scrolling. I'm using a white MacBook (the late 2009 model) running Mac OS X 10.7.4 (Lion) on a 2.26 Ghz Core 2 Duo with 2 GB ram. Lion's memory management seems to be quite terrible, so I was looking for a less memory-intensive replacement to Chrome, where I often have around 30 tabs open at any given time. When I read about—and subsequently installed—Slimbrowser, it seemed to be a good alternative, until I tried scrolling. It just didn't work, at least not up to speed. The page very slowly moved down, but not at a constant rate, and often with quite jerky movements. But when I stopped scrolling, it continued to move on down. And if I waited until it stopped, the place in the page that it stopped was, presumably, the place where a "normal" scroll would have landed me. I'm not an extremely technical person, but I would guess the redrawing speed is also the problem in my case here. I don't have any CPU issues that you mentioned, but scrolling is definitely a problem. Any advice on how to downgrade to 5.01? Maybe that's the only solution until they get this bug worked out.