Was sitting playing cod, as i have done lots over the holidays and a fan in my PS3 suddenly comes on - ive NEVER heard it do this before? It was properly noisy too, put my hand at the back of the console and its blowing out a fair amount of air.

It had been on for about 3hours in my room, not overly warm or anything. Had it on much longer and never had the fan turn on before.

Anything to worry about or has it just got toasty and decided to get rid of some warm air?