Under load, the heat wins.

All four cards climb fast under load. Three of them pin at 93 °C — the thermal-throttle ceiling — while GPU 1 (cyan) stays comfortably cooler. Watch the combined both phase.

The consequence of the heat: as the hot cards hit 93 °C their SM clocks collapse — GPU 3 drops below 1 GHz. GPU 1 holds full boost throughout.

Each card is capped at 600 W. GPU 1 sits on the cap (power-limited, not heat-limited); the throttlers fall well below it because thermals — not power — are the bottleneck.

The damning detail: the throttling cards run their fans at 100 % and still overheat. This is an airflow / card-spacing limit, not a fan-curve one.

64 threads hold ~4.7 GHz all-core, but Tctl rides the 95 °C ceiling — the Threadripper is thermally limited too, just gracefully.

Every row is one logical CPU; colour is its clock. During GPU-only just a handful of cores boost to feed gpu-burn; during CPU and both the whole die lights up at sustained boost.

Measured during the 5-minute combined CPU+GPU load — the worst case.

Values as min · mean · max over each phase.