There's no denying that Intel's Core i9-14900K is a power hog. This article examines the power, performance and thermals effects of limiting its power consumption, with very interesting results. Additionally, we investigate undervolting to determine if efficiency can be optimized even further.
Part of it is operating at a more efficient point on the VF curve. The other part is that Intel parts increase voltages by ~2.5mV every for every degree C closer to TjMax. A part at 95C@253W has a 50mV worse VF curve than a part at 75C@190W which can be a substantial efficiency difference.