The ‘Average CPU Power’ is based on ‘average’ use, which is explained on Wikipedia.

According to Wikipedia, the Thermal Design Power is the maximum power consumption for thermally significant periods running worst-case non-synthetic workloads (cf. this article). If we assume that the bulk of the electrical power consumed by a CPU is converted into waste heat, then the TDP can be a reasonable approximation for the amount of electrical power a CPU would consume under a worst-case, real-world load.

I used cpuburn to generate such a load. There was no IO load on the system during the tests. I measured power draw with an off-the-shelf Kill-a-watt, so these results should be taken with a grain of salt.

The data indicates that the idle vs. full load power consumption difference for one CPU is 70 to 75W.

If we assume the power consumption under full load is 115W (the TDP for the processor), then idle power consumption would be 40 to 45W per CPU. That would put idle power consumption at 35-39% of its TDP for this particular CPU.

Apologies for the low quality picture – I only had a crappy cell phone camera on hand…

I suspect that amount is way too low to achieve all that much, at least if the idea is to build high speed rail in densely populated areas: consider the cost of the inevitable eminent domain to improve tracks and/or build high-speed tracks. I’d like to see rail funding on par with airline subsidies – but at least this is a start.

I do worry about the definition of high-speed. Amtrak’s Acela Express is as good as it gets in this country, but it’s a far cry from what is considered high-speed rail in Europe and Japan. As the wikipedia article explains, this is mostly due to track quality and the fact that the Acela does not run on tracks that have been purpose-built for high-speed rail. Seems like there is lots of room for improvement by upgrading sections of track – but Amtrak does not actually own some of the slowest parts of the track…

At least the increases in (Acela) ridership are promising – the monthly performance reports show rising ridership for Amtrak as a whole, and the Acela in particular. I suspect that trend will continue in the foreseeable future as flying is such a hassle these days.

These measurements were made with Firefox in full-screen mode (F11). The built-in USB hub was not connected to the computer.

As you can see what Google says is correct for this 20″ LCD monitor at 1024×768 resolution: there is no difference in power consumption between http://google.com and http://blackle.com. However, at native resolution (1600×1200), there is a small difference in power consumption (0.02A). Most people can be expected to run the monitor at this resolution.

The effect of changing the brightness is much more pronounced than the difference between Blackle and Google (previously I erroneously mentioned that changing the brightness had no effect; I was in fact changing contrast, the on-screen-menu for this monitor is not the most userfriendly).

Viewsonic claims a typical power consumption of 52W, which is very close to what I’m seeing here at 1600×1200 with brightness set to 100% (48W). But the VA value is 85, which means this monitor has a pretty crappy power factor (PF) of 0.56. Compare that with the Antec EarthWatts 380 power supply I bought for this new computer, which has a PF of 0.99! The wikipedia page on power factor correction is pretty fascinating reading if you want to know what Viewsonic could have done to improve the power factor.

The ‘sleep’ power consumption is not so bad at about 1W, but I will still switch the thing off when I’m not using it. One Watt 24/7 is over 8.5 KWhr per year, which is a lot of energy to waste.

The monitor has a power off switch on the front, but that makes no difference in terms of power consumption compared to sleep mode; it still sips 0.01A. Fortunately there is a real off switch at the back next to the power plug as well.

Check out the website, too, particularly the advice on how to reduce your CO2 ‘footprint’.