This is something I've wanted to know for quite some time. From the Powerbook 15" running 10.3.1 I bought several years ago, through to the MacBook running 10.4.10 that I currently use - I've consistently noticed that pages with Flash content often cause my fans to run very fast and my CPU temp to spike dramatically. What's strange is that the same, identical pages when viewed on a PC don't seem to produce the same effect i.e. the PC's temperature/fans remain at normal levels. And what's even stranger is that not all Flash content seems to produce this effect on my Macs, only certain sites... So what's happening here?? Is Flash just not very well implemented on Macs (i.e. is it Adobe's fault?), or is it a problem with Safari's webkit/Mac architecture? If Safari is the culprit, does anyone know if this is fixed in Safari 3.0?