It seems that the latest models of the MacBook Pro are struggling when running demanding tasks such as compiling code or rendering 3d scenes. There are already a pile of user posts in Apple support forums about the issue and as the problem is easily reproduced its likely that Apple engineers are working on a solution as we speak.
The problem (as reported by users) is that the machines seem to overheat and lock up entirely. Advice for the moment is to quit as many open applications as you can when wanting to run intensive operations in an effort to minimise problems and reduce the likelihood of a freeze.
Not what you would call a great start for Apple and somewhat over-shadows the introduction of Thunderbolt and improved graphics. Whether Thunderbolt lies at the heart of the problem or its something like a graphics driver issue remains to be seen.