Powermaster Performance Mode
The PowerMaster Performance Mode also enabled SpeedStep, causing all Pentium 4 600 series and Pentium D processors to reduce their clock speed to 2.8 GHz when idle. As soon as there is a system load, PowerMaster will increase the FSB speed by 5%. This causes an overclocking of both the system clock and the processor, which can be considered safe, as a tolerance of 10% will always work.
Powermaster Silent Mode
In Silent Mode the system never operates at settings that exceed the specifications. In our case it's always a system clock speed of 200 MHz. As soon as the system is idle, PowerMaster reduces the FSB speed to 140 MHz only. In combination with Enhanced SpeedStep, we got a core clock speed of less than 2 GHz, which could theoretically be cooled passively. However, we do not recommend doing so, since the thermal dissipation will increase again as soon as there is a load and PowerMaster switches back to full FSB speed.
