Keeping Cool When Power Consumed Tops 150 Watts at 4.1 GHz
The dark side of overclocking a CPU is the heat produced when consuming enormous amounts of power. Since our Pentium D 805 CPU was built using 90 nm fabrication technology and implements a dual core design, power consumption at clock speeds over 4 GHz climbs to extreme levels.
The O5A designation on the packaging describes the CPU's energy class.
According to the "Platform Compatibility Guide", this CPU consumes 95 W of power at its standard clock rate - the 05A abbreviation that appears on the packaging represents the PRB0 specification. Of course, this also means that the CPU cooler that's bundled with this processor is designed only for such relatively modest power consumption levels.
This is the stock cooler packaged with the CPU.
An excerpt from the datasheet for the Pentium D 805
At a standard CPU clock speed of 2.66 GHz, Intel specifies maximum power consumption of 95 W. On a purely mathematical basis, this produces theoretical power consumption levels of 142 W at 4 GHz.