PC Power Management, ACPI Explained In Detail

DK writes "Computer performance has increased steadily in recent years, and unfortunately so has power consumption. An ultimate gaming system equipped with a quad-core processor, two NVIDIA GeForce 8800 Ultra, 4 sticks of DDR2 memory, and a few hard drives can easily consume 500W without doing anything! To reduce power wastage, the industry standards APM and ACPI have been developed to make our computers work more efficiently. ACPI is the successor of APM and is explained in detail in this article."

ACPI?

[crankyspice]

2002 called, it wants its Page 3 tech story back.

Not worth reading this crap

[Aranykai]

Im sick and tired of having to view 11 pages of adds to read an article that could easily fit on one. Easily 6 adds per page.

The Wikipedia ACPI article is better and doesn't shove crappy adds down your throat. http://en.wikipedia.org/wiki/ACPI [wikipedia.org]

Zillion watt monsters

[Anonymous Coward]

Why do we even have a distinction between the low power graphics card brands anymore?
I understand the uber top end being power hungry, but after that?
Why isn't the nVidia line up:
GeForce 8800 GTX-Hyper-turbo-mega-power card extra bonus edition
GeForce 8800 Go
GeForce 8600 Go ...

I'd pay for a "mobile" chip on a PCI-E board...
Then couple it with a "mobile" processor, some low noise fans, harddisk and whatnot and you get a reasonable but very quiet gaming box.

How it is supposed to work

[niceone]

TFA lists all the states and how all this power management stuff is supposed to work... what it doesn't go into is how (or if) it actually does work. My experience is that it doesn't - I press sleep on my Windows XP PC ans all I get is a message telling me that the driver of my MIDI controller keyboard will not let the machine go to sleep!

And on my (admittedly very old) Ubuntu laptop the screen just blacks out for a couple of seconds and then comes back on again. When it was running windows it used to go to sleep fine, but the wireless wouldn't work when it woke up.

I guess other people's mileage probably does vary...

Re:OS

[Whiney Mac Fanboy]

anything less then a 500w psu and it'll be under powered.

Oh Bollocks. Vista might be shit and power hungry, but many laptops with a sub 100w psu will run it just fine.

Comment removed

[account_deleted]

Comment removed based on user account deletion

No, I didn't read the fucking article.

[adolf]

ACPI has been around for almost eleven fucking years. In-depth information about it can be had in all of the usual sources, from LKML to Wikipedia to decade-fucking-old back issues of Byte and PC Magazine.

News? Where?

Re:OS

[tsa]

That means staying of the uber-high end stuff, which historically always had a bad power to performance ratio.

The problem with uber-high end stuff is that in two years it's mediocre and there is new uber-high end stuff that uses even more power. So old stuff uses relatively less power than new stuff, but still power consumption goes up over the years wehn you buy new computers. That trend must be broken.

Sleep is worthless

[paul248]

Being able to put components to sleep is pretty much worthless if you want to run anything resembling a server. Hardware manufacturers need to focus less on sleep states, and more on making components consume less power while they're active.

A good first step is the 80plus [80plus.org] initiative for power supplies. By increasing the power supply from 65-70% to 80-85% efficiency, you gain a decent amount of active power savings right off the top. If you care at all about conservation, make sure to check the efficiency rating of your next power supply.

The people at Intel and AMD have made great strides toward power efficient CPUs, which can scale back their clocks on-demand without noticeably hurting performance, but the real remaining problem areas are in video cards, RAM, and especially hard drives.

The ideal computer would consume almost zero power while sitting there doing "nothing," but be able to wake up at a moment's notice to handle requests from the user or the network. Power management should be hardware-based and completely transparent. ACPI is just a dirty hack that's becoming more useless as network accessibility becomes more important.

Convenience...

[C10H14N2]

After one particularly eye-opening electric bill, I started putting everything on timers, save one computer and my fridge. If I'm asleep or not at home, the power gets cut. ...at the prevailing rates around here, 1W constantly burning all month is about $5. So, $35/month just to let that A/V system sit idle. For the average person, that's about two hours of work. So, unless it takes four minutes out of your day, every day, it's not worth it. Considering we're probably talking more on the order of ten seconds per day, unless you are making in the neighborhood of $400/hour, you're "convenience" literally isn't worth it.

worthless for servers, great for pcs

[tknd]

I agree that sleep is worthless for servers but it's great for pc users. For example my parent's dell c521 desktop when sleeping takes only 2-3w at the plug and 'appears' to be off (all fans stopped). It only takes a second or two to get back to the desktop and applications are left as they were. I also agree that hardware vendors (especially graphics and chipset makers) need to focus more on low power solutions not only for laptops but also for desktop and server machines. The cpu vendors have been working on it already and intel has been pushing things like centrino and santa rosa for laptops, but I see no reason why these technologies can't also be applied to desktops and even servers which typically get left on all the time if not quite often.