Motherboard Hardware-based Energy Saving Feature

[Emoz93]

Asus - EPU (Energy Processing Unit)
Gigabyte - Dynamic Energy Saver (DES)
MSI - Active Phase Switching (APS)
ASRock - Intelligent Energy Saver (IES)

These motherboard hardware-based energy saving feature are supposedly able to reduce the power consumption of the computer. But how much is the difference in energy saving? Does it even work?

[Gilly]

Yes they do work, however they do not save as much energy as Speedstep (Intel CPU's declock with light/ no load) for example.

I can't remember the article I read, but you are better making sure speedstep etc is enabled, then you can maybe look at power saving options, but swapping hardware is an expensive way to save energy.

A 25W LCD compared to a 150W CRT monitor would save 125W every hour. With a cost of £200 for said LCD monitor, and at say 15p (£0.15) per KWh, it 8 hours to save 1KWh. So it would take (200/0.15)*8 hours to pay for itself. That is over 10600 hours, or about 1 and a half years of constant use.

Depending what your energy saving reasoning is, you might just be better forgetting the energy saving features of the motherboards, no doubt it is better for the environment and your pocket, but nothing saves as much energy as not having the device on at all :P

[Paradigm Shifter]

I remember seeing a test from one of the bigger hardware review sites that covered these power-saving techs... they varied terribly. Sometimes they'd save you a few watts, other times they would do nothing.

They certainly don't have anywhere near the impact of Speedstep/Cool 'n' Quiet, drive idle powerdown and 3D/2D GPU clocking.

Seems like half the time all they do is poll the USB ports and go, "Oh, that one doesn't have anything plugged in, I'll turn it off!"

[Emoz93]

So that means that the mobo's energy saving feature is not that effective.

[Paradigm Shifter]

Indeed.

Stick to the CPU/GPU manufacturers energy saving systems. They work. The mobo manufacturers ones... not so much.

[Emoz93]

Intel SpeedStep is disabled in the BIOS by default. If I enable it, is that all I need to do if I want to reduce my PC's energy consumption?

[Delphium]

Intel SpeedStep is disabled in the BIOS by default. If I enable it, is that all I need to do if I want to reduce my PC's energy consumption?

Correct, it works automaticly.
It essenitally runs the CPU at a lower clock rate most the time, then when you get more active it will bring it back up to the normal stock speed. :)
This will mean less power usage and waste heat :)

[Emoz93]

Correct, it works automaticly.
It essenitally runs the CPU at a lower clock rate most the time, then when you get more active it will bring it back up to the normal stock speed. :)
This will mean less power usage and waste heat :)

Does SpeedStep also determine when the PC goes into sleep mode if the PC is idle for a certain amount of time?

[Delphium]

[quote]Correct, it works automaticly.
It essenitally runs the CPU at a lower clock rate most the time, then when you get more active it will bring it back up to the normal stock speed. :)
This will mean less power usage and waste heat :)

Does SpeedStep also determine when the PC goes into sleep mode if the PC is idle for a certain amount of time?
No SpeepStep does not determine when the PC goes to sleep.
Setup the power management in windows so that the pc will sleep after say 20mins of inactivity.
In win7 you can set this up by...
right click on the desktop, select personalize, click screen saver which will open a new window, at the bottom click "change power settings", this will open yet another window, where you may select a profile and "change plan settings" then click "change advanced power settings". You can then tweak the settings according to how best suit your needs :).