I don’t think it’s as much reducing performance, as it is stamping out poorly optimized cpu calls that make it work harder than it should.

Several reviewers I saw all said that the heat up issue is not consistent with doing performance work. One of them spent the whole day shooting 4k in the sun and the phone was fine. Then he went to use spotify while in airplane mode (literally on a plane) and the phone just started heating up for no reason.