Firefox seems to be having a "lets hog lots of cpu resources" moment on my mac. infact it was almost maxing a cpu core

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running firefox 2.0.0.5 on osx on a macbook
All I had was Cableforum open, have had to restart it twice so far because of this.
Its not the first time its done it either, pc has been known to do it ocassionly but the OSX version seems far more prone to doing it.
Any ideas how to discipline the naughty little fox.