Over this past weekend, I decided to build a new general purpose workstation from parts, with a goal of getting great performance with the lowest power consumption possible. The nice thing about building a Windows based machine is that you can choose the exact components that you want based on what you are trying to achieve. You are not stuck with what Apple thinks you need. In this case, I wanted to replace a 2008 vintage, 45nm 3.0GHz Core2 Duo E8400 based system with something that would have better performance and use less power.
I choose to build a 32nm 3.2GHz Core i5 650 based system, using an Intel H55 chipset. This processor has pretty decent integrated graphics (as long as you are not a hard-core gamer) when used with the H55 chipset. The Core i5 650 is a dual-core CPU that has hyper-threading and Turbo Boost technology. This means that the operating system sees four logical cores, and that individual cores can be over-clocked when the other cores are not busy. This helps single-threaded performance, which is a very common scenario with many desktop applications.
Below is a list of the key components, with production information links and pricing:
You will get better energy efficiency for a low electrical consumption system if you use a lower capacity power supply. If you get a large 1000 watt power supply, it will be less efficient than an identical 400 watt power supply when you are only using 40-50 watts of power. The Seagate Momentus XT hybrid hard drive performs much better than the 5900rpm Western Digital Green Power hard drives that I have used in the past for energy efficient systems. This system only draws 30 watts of power at idle, after Intel SpeedStep has throttled back the processor to 1.2GHz. That is laptop territory. It draws 50 watts with the processor cores pegged during a benchmark test. By contrast, the E8400 system uses 72 watts at idle. I use a Kill-A-Watt meter to measure the consumption for the entire system.
The Windows Experience Index numbers for this very green system are quite impressive compared to the older E8400 system:
i5 650 E8400
Processor 6.9 6.6
Memory 7.3 6.7
Graphics 4.8 5.0
Gaming 5.3 6.3
Hard Drive 5.9 5.7
This new system boots and goes in and out of sleep mode extremely fast due to the hybrid hard drive. The Core i5 650 system has a GeekBench score of 5296, while the older Core2 Duo E8400 system has a score of 2375. Significantly better performance at less than half the power consumption is a great combination.