Reducing the Power Consumption of Overclocked PCs

babyshiori writes "Now, that must sound pretty inane. After all, overclockers employ all kinds of power-guzzling methods to improve their CPUs' overclockability. However, there are many good reasons to do so. In this guide, we will not just look at theoretical tips on reducing power consumption in overclocked PCs, we will also look at how well they work in real-life situations. Best of all, we are shown why they will improve our PCs' power efficiency without any real loss in performance. Start doing your part in saving the planet now!"

Comments

Not so silly

[NMerriam]

I don't know why people are being so negative about this article. It isn't trying to convince you that overclocking is the most energy efficient thing to do, it's trying to show you ways you can be more energy efficient if you do choose to overclock. People who overlock do so because they want higher PEAK performance, not because they enjoy wasting energy 24/7. When you're not in need of that peak performance, it only makes sense to go ahead and be efficient.

The whole article can be summed up by saying:

1) Be sure to enable whatever idle tech your motherboard/processor supports (speedstep, cool'n'quiet) so that it automatically slows down the CPU and power consumption when not under load.

2) Try undervolting, use stability tests to find the lowest voltage your particular CPU can use, rather than simply using the default.

3) If your motherboard/processor comes with some software that lets you configure the clock speed/voltage on-the-fly, go ahead and test stability under different settings and save those configurations and use them when appropriately. I'd add that most video cards have the same type of software these days -- go ahead and overclock them when you're gaming, and be sure to slow them back down when you're done.

Neither of those should be shockingly new ideas to anyone who's been building computers for years, but anyone new to it should find the article informative in the specifics.

Quite untrue

[Kupfernigk]

The efficiency in instructions per joule of the cpu alone may increase somewhat with underclocking, but the efficiency of the system as a whole may not.

This is because the cpu is not the only energy dissipator in the system and the others exceed it. To take a very simple example: I have a build which takes 30 minutes. During that time, the hard drive is on all the time, so is everything on the motherboard. To be very conservative, assume that at maximum speed the cpu uses 50% of system power.

Now I underclock the processor to, say, 60% of normal speed, and am able to reduce the voltage, and hence the power consumption, by 50%. The system power consumption is now only 75% of what it was. But my build takes around 50% longer. So I use 75% of the power for 150% of the time. The energy consumed in the build is 12% higher with the underclocked cpu.

The concept of getting the most processor speed when needed and powering down unused subsystems whenever possible is the one to give the best power saving. As a further example, replacing an old 4200rpm disk on a laptop with a 7200 rpm disk (where possible) may actually improve battery life because the disc is active for much shorter periods (with twice as much data per track, and 12/7 the speed, it can read the same amount of data in roughly 1/3 the time of the slower drive, which outweighs its 50% higher active power.)

Re:Saving the world

[DarkOx]

The other thing to consider is maybe we should look at increasing the lengh of the hardware life cycle rather then constantly cutting it. We should start demanding that software vendors start producing tight efficent code again so that we don't have to keep replacing our machines to use it. We should demand hardware vendors produce platforms that have a long life span with an upgrade path that enables most components to be resused as much and as long as possible.

These is all speaking of primary systems.

I had my first PC, and 386DX-20 for almost 10 years(MSDOS and later Windows 3.x added).
My second system a Gateway P5-90 for about 5 years(MSDOS and Windows 3.x).
My third system home built Cirix 8686-233 for about 3 years(Windows 95 and later 98)
My fourth system home built K6-2-450 for about 2 years(Windows 2000, later Slackware 8 after ---------frustration with the performance of win2k)(would have kept it longer but it broke)
My fifth system now about 8 years old Athlon-800 (Slackware 10.2 and now 12.0 I am even using compmgr on X and enjoying sexy transparent windows!) (works fine with my lowly geforce2-mx400)

Scary trend in that propriety software world. Other then playing and encoding some video MPEG2 and 4 are fine some of the more recents ones are pretty slow to encode and difficulte to play back properly; I can do just about everthing as well with my 8 year old box as can be done with a brand new one. I chose software that is not wasteful and can thefore get allot of miles out of a machine now. I grant you I am not a PC gamer, I have a Wii for that. I am pretty confident the enviornmental impact of my having replaced this machine at least once if not more then once in the Commercial software world would have been greater then any questionable power efficencies of this older equipment, CRT included. The power draw of PCs has not exactly been trending down in general so its likely new gear would save little there at all if anthing the main offset being an LCD rather then the CRT.