X220 always running overclocked

[Jaster]

I have an x220 with an i5 2540, rated at 2.6GHz. According to my CPU meter it is constantly running at 3.1-3.2GHz, whether on AC or battery, giving me very little battery life and more importantly causing the CPU to run in the high 70s to mid-80s temperatures with the associated fan noise.

Is there a way to reign it in a bit? It is my understanding that turbo boost is only supposed to kick in when the computer needs the power, whereas mine is running all the time. There's nothing obvious in the power manager apart from the Lenovo turbo boost which is switched off, and IIRC, only causes the fans to throttle up and has no effect on the CPU itself.

EDIT: Just updated the BIOS and I seem to be back to business as usual. The system is running much cooler and the CPU is dynamically clocking itself as appropriate. No idea what the cause was, however the BIOS version I had was very old as I'd been holding off on updating it as I didn't know if it would work with my external GPU. Turns out it does, and all is well!