Thermal Power Loss
The Silverthorne Atom processors for notebooks and UMPC are fitted with the mobile version of the 945G chipset. The northbridge has an energy consumption of 4 watts and the ICH7M southbridge a consumption of 1.5 watts. Since the embedded board has the Diamondville version of the Atom, ECS has soldered the 945GC chipset. Technically speaking, there is no reason why the energy saving 945 chipset should not have been used ; this would have been the ideal solution, but then the board would have cost considerably more.
The desktop 945GC has a TDP of 22.2 W and the southbridge uses 3.3 W. Compared to the Atom 230 processor which has a TDP of 4 W and is supplied with a voltage of 1.088 V, this is a considerable difference.
The board is fitted with a one-phase regulator for the power supply to the processor. The ITX board with a Mobile Celeron 220 that we are comparing it with also has a single regulator unit. Due to the relative low price of the Atom ($29), it has no energy saving functions such as SpeedStep — it always clocks at the full 1.60 GHz. We measured the energy consumption of the overall system plus power supply — the Coolermaster PSU we used had an efficiency of over 80%.
In idle mode, the Atom 230 system was able to set a record for our lab at just 40 watts, but compared to AMD’s 780G platform with a Sempron LE-1100, its lead was only 3.4 watts — not exactly spectacular.
Under full load, the Atom 230 at 11 W is a considerable improvement over its predecessor, the ITX board with the Mobile Celeron 220.