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Yeah I've noticed this too, it only happens when in full screen on youtube. I can be in full screen on other video streaming apps and fans are normal.

Anyway to fix this???
 
By comparison, I am watching YouTube on Linux on an ASUS eeePC, which has a Celeron 900MHz downclocked to 630MHz and a GMA9xx intel GPU.

Not. A. Murmur.

oh come on.
Apple or not, you seriously can't compare a full blown Core 2 Duo processor to an underclocked, specially designed low power using CPU, such as the Celeron mated to equally slow/low power hardware. The C2D is going to run hotter just sitting idle.
 
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