That's a decent method for some purposes, though it's not without its own flaws. For systems using integrated graphics or any laptop, the CPU's thermals are intertwined with the GPU's. You may also have a workload that sends a CPU core to its highest stable clock speed and safe voltage, but is still cooled well enough that the CPU doesn't get close to its temperature limits. Or you could have a situation where the CPU can tolerate a higher temperature, but it has to throttle so as not to burn the user because a fair chunk of that heat is being conducted up through the keyboard and down into the lap.
> but it has to throttle so as not to burn the user because a fair chunk of that heat is being conducted up through the keyboard and down into the lap.
I've never used a mobile device that seemed to have such considerations. They all seem perfectly happy to make their surface scalding hot. Do manufacturers actually care about this?
Perhaps in stable environments that would be reasonable, but it would also mean that if I put my laptop in the sun, the system load should become large and potentially (hot heatwave sun on a dark laptop) exceed 100% even if the laptop is completely idle.