I have dealt with dozens of laptops over the years that simply cannot withstand maintained 100% CPU usage for more than a short while using stock cooling. Not one (although to be fair they're mostly mid-line laptops, no serious gamer-performance machines).
Mostly, laptops seem to do one of two things when pushed this way, (1) power down/overheat, or (2) throttle the CPU back to force temperatures down.
Is this simply a common issue with laptops (which often have little space for adequate fans), or what? I have never noticed this trend to the same extent with desktops. I have several desktop/servers that can grind away at 100% CPU for days under various stress tests or server applications and never break a sweat (so to speak), even though they almost all use stock cooling.