But in a smaller device like a 7-8", the left over energy which cannot be dissipated turns into heat.
All computing energy* is "left over" and turns into heat. All that
heat will dissipate. The difference is that under steady state
conditions a small device will generally need to get hotter than
a big device to dissipate a given amount of heat.
Two Watts in a 40 PDIP can give you a finger burn that you'll
never forget. Two Watts in a 299 CPGA will feel cool to the
touch.
If you run the benchmark once, however, it may be a short enough benchmark to show a high score before heating up and/or throttling down.
Agreed.
*Except for an infinitesimal bit radiated (or in the case of
line powered devices - conducted) away as EM waves but
EMI/EMC rules keep this portion extremely tiny.