Clamshell Mode CPU Throttle?

Hey folks,

I was just wondering if anybody here has noticed that when working with thier MacBooks in Clamshell mode that the performace is... well... sluggish.

Granted I have an older MacBook (late 2008 13 inch model), but I have noticed that the performace just isn't the same when the lid is closed and hooked up to an external monitor. I do notice however that if the lid is open and I am working with a mirrored display the performance is what it would be when running just the internal display.

My therory is that due to excess heat when in Clamshell mode, in order to support it Apple has designed it so the CPU will throttle down when in Clamshell mode.

Anybody else notice performance issues (other than the slow wifi bug) when running in Clamshell mode?

Cheers!