10 IT Power-Saving Myths Debunked

snydeq writes "InfoWorld examines 10 power-saving assumptions IT has been operating under in its quest to rein in energy costs vs. the permanent energy crisis. Under scrutiny, most such assumptions wither. From true CPU efficiency, to the life span effect of power-down frequency on servers, to SSD power consumption, to switching to DC in the datacenter, get the facts before setting your IT energy strategy."

Comments

Questionable grasp on the problem space.

[Anonymous Coward]

Myth No. 3: The power rating (in watts) of a CPU is a simple measurement of the system's efficiency.
Fact: Efficiency is measured in percentage of power converted, which can range from 50 to 90 percent or more. The AC power not converted to DC is lost as heat...Unfortunately, it's often difficult to tell the efficiency of a power supply, and many manufacturers don't publish the number.

I'm not sold on taking advice who doesn't understand the difference between the wattage rating of a CPU and the wattage rating of the power supply. They're completely different components.

Re:Questionable grasp on the problem space.

[gmack]

Myth No. 9: Going to DC power will inevitably save energy.
Fact: Going to DC power entails removing the power supplies from a rack of servers or all the servers in a datacenter and consolidating the AC-DC power supply into a single unit for all the systems. Doing this may not actually be more efficient since you lose a lot of power over the even relatively small distances between the consolidated unit and the machines. New servers have 95 percent efficient power supplies, so any power savings you might have gotten by going DC is lost in the transmission process. Your savings will really depend on the relative efficiency of the power supplies in the servers you're buying as well as the one in the consolidated unit.

This is completely wrong. The author missed out on two of the three power conversions that take place in a data center. Data center UPS units take the AC current convert to DC then back again just so the server can convert it back to DC. Even if you have 95% efficiency at each stage the conversion losses will add up.

People wouldn't be going DC if it didn't result in measurable power savings.

Debunk this

[sargeUSMC]

Taking ten suppositions and making suppositions about those suppositions (I'm getting dizzy) is not debunking. All I see here is lots of questionable, completely unattributed information. For example: "The average 17-inch LCD monitor consumes 35 watts of electricity". Really? Where did this information come from? Did you pull this information from the glossy for a 17" monitor? Did you just test your monitor? Did you test a large sample of monitor's here? Did you pull this information from a study? Out of your ass?

Re:I dunno..

[R2.0]

I stopped reading at #1: "Fact: The same electrical components that are used in IT equipment are used in complex devices that are routinely subjected to power cycles and temperature extremes, such as factory-floor automation, medical devices, and your car."

Well, yes, except for the fact that the it's a total lie. Cars, factory automation, and medical devises most certainly do NOT use "the same" components. While they may do the same things, and even be functionally equivalent, they are rated to much higher temperature and stress levels than consumer or even server grade components. Just ask the folks who have been trying to install "in-car" PC's with consumer grade components.