http://www.macrumors.com/2011/03/21/...ng-under-load/A lengthy discussion thread on Apple's discussion forum reveals an issue that some new 2011 MacBook Pro owners have been having with their new machines.
There's been speculation that the issue is related to the graphics driver or power management, and it seems the issue is reliably reproducible. A wiki has been organized to document the issue. Apple is reportedly aware of the issue, but no reliable solution has been provided.