Si, creo ke los PIV traen Speedstep, pues mira en el video ke aparece en el link ke puse arriba, cuando quitan el disipador del PIV y andan jugando quake, se caen los FPS como a 15 y segun la explicacion de tomshardware es debido a que el proc reduce la velocidad para generar menos calor:
"The Pentium 4 core comes equipped with a thermal monitoring unit that permanently checks the temperature. As soon as the core temperature has reached a certain trigger value, the thermal unit throttles down the clock of Pentium 4 until a safe temperature has been reached.
This solution is clearly commendable and proves that Intel's idea of equipping Pentium 4 with clock-throttling was far from a bad idea, as some sources want to make us believe. It is pretty much impossible to 'fry' a Pentium 4 processor. Additionally, Pentium 4 remains operational even once the thermal catastrophe took place and the heat sink fell off."