Conclusion: Core Duo Loses The Platform Game
If you are serious about making a low-power system, there is no alternative to going for a mobile processor and a motherboard based on a mobile chipset. Both are more expensive than conventional components, but they allow you to achieve a total system power consumption of less than 40 W (not including the display). You need to reach a power draw of approximately 60 W in order to assemble a system that works sufficiently well for most applications, however. In this context, platforms based on the Pentium M or the Turion 64 remain unbeaten.
Our conclusion for the Core Duo processor is particularly interesting, because in theory it is capable of enabling the assembly of a dual core desktop system that requires only 45 W. This, however, requires a motherboard that uses the 945GM chipset, which is not yet available. Using AOpen's 975X motherboard forces the user to go for discrete graphics, which drives the system power consumption to a minimum of 70 W. Several motherboard companies are currently working on desktop motherboards for Core Duo, but most do not deploy the 945GM chipset into the desktop. Core Duo is a great product and is very efficient, but it stumbles due to the lack of a suitable low-power desktop platform. (Ironically, it was Intel who has been trying to refocus the industry to think about platforms...)
Efficient systems depend on efficient components, and there is one component that lately has turned into a serious energy hog: the graphics card. The $500 monsters from ATI and Nvidia consume 100 W or more when doing their 3D work. Even the basic requirement is at least around 20 W, which would seem to make high performance and energy efficiency mutually exclusive.
But wait a minute - there are graphics solutions that work without excessive power requirements. Have a look at the products that both ATI and Nvidia send into multimedia and gaming notebooks: there is the Mobility Radeon and the GeForce to Go, both of which include technology that helps conserve energy. How about offering PCI Express graphics cards that are based on mobile graphics solutions? Although the market certainly is not huge, it seems like there are would definitely be interest. Such products would also help in the comparison of different mobile graphics solutions, by running them on a reference system.
The bottom line question is simple: does a low-power PC make sense for you? We recommend first finding out your energy costs per kWh (kilowatt-hour), and then calculating how much energy would be consumed over the course of a year if you operate the system 24/7. An example would be 100 W of power consumption times 24 hours, times 365 days. The result is 876 kWh, which you have to multiply by your energy cost per kWh.
It is obvious that any high-end component would spoil your saving efforts. For example, we cannot recommend buying a Core Duo T2600 in order to reduce your energy bill. Instead, go for the mid range; here, Turion 64 solutions currently offer the best bang for the energy saving buck. But the Turion 64 X2 will be available soon, and the first 945GM motherboards for Core Duo should also hit the retail in the not too distant future. We expect both to renew the energy efficiency debate.