5 windows open (maybe 20-30 tabs in all). Seems to be using 1.5Gb of memory. Is really slow to respond to typing or browsing. Sample to be attached.
Created attachment 19764 [details] Activity Monitor sample
The CPU time is all being spent below -[QTMovie idle], which appears to be part of the QuickTime plugin. Based on the sample the CPU usage does not appear to be a WebKit issue.
Okay, I'll report it to Apple then. If it makes any difference - the movie was paused and not playing.