Actually I don’t know it’s caused by Safari or Flash. But my observation is Flash can drive your Mac like a heater, may be it’s good in the winter.
When started using Snow Leopard 10.6, Safari can nicely release CPU resource when you minimize it or changing to other tab. However, it’s not the case after updating to 10.6.1 (with Flash security update) or 10.6.2. Until the Safari update 4.0.4 Apple just released, the problem can be really solved. Hope this will not come back forever!
I still agree Flash is not capable to fit into mobile device unless they can have their code be more environmental friendly!
All Facebook games are Flash monsters, they keep releasing CO2. CPU now running at 105% and machine temperature went up to 80C and even higher!
Switched to my blogging tab, CPU usage by Safari dropped to 35% and temperature is going down.