I’m noticing a substantial slowdown when in full-screen mode. I have a MacBook with 4G of RAM, not running anything other than Firefox alongside Scrivener, but full-screen mode has slowed down to the point of inconvenience, with a noticeable lag between the time of typing a letter and the letter appearing on screen.
Thanks for the report. I’m guessing you updated to Snow Leopard. Unfortunately 10.5 slows the text system down a little, and some of the extra things Scrivener does is not playing well with it, especially in full screen mode. I recently spent a month optimising this and fixing it for 2.0, but it’s harder to do in 1.x because it relies on other underlying changes, but I am looking into what I can do.