Underclocking

[Bleek]

A break from the norm, I've been working on a low energy ultra quiet work PC, for home.

I've got an ASrock A780GM-LE (780G Socket AM2+) mATX, a Dual Core Athlon 5000+ Black Edition, 2GB Geil Dragon DDR2, 1 x 40GB Maxtor 200W PSU and no other devices.

I've managed to clock the Athlon down to 2GHz at 0.78v down from 1.4v and the memory down from 1.8 to 1.65v! It uses 5w at idle and runs at 31'c stock AMD cooler even in these hot conditions (ambient of 29-31). It'll only get cooler as the weather calms down.

The whole system is consuming less than 25W in general use (tested at the wall socket), that's what you call cheap computing and it's by no means slow (I trade so use large charts and spreadsheets).

Anyone else had fun underclocking at all?

 

[Bleek]

Well I have to say I've had great experience with ASrock in the past and this board is no exception, the voltage changes are in 0.01 increments and can down as low a 0.5volts for the cpu?! Madness.

I might see what I can boot at those volts.

I'm really pleased with 2GHz @0.78v though, that's ultra efficient surely?

Any bets on 1.8GHz at 0.65volts?

 

[Bleek]

Which athlon is that i have the brisbane 2.7 only trouble is my mobo only goes down to 1.3v core

65nm Brisbane (5000+ Black 2.6GHz).

 

[Bleek]

What minimum cpu speed could you get away with it if it was just a media server stuck in a cupboard? I have various old cpus and motherboards kicking about which I could turn into a 24/7 media sever of some sorts and I guess the lower the power consumption the better. I would just want it to host all my music files and perhaps act as a central backup for general file serving. At what cpu speed does this become impractical or will it always be limited by the network speed or other factors?

A modern cpu won't struggle at all, your HDD will always be your weakest link for streaming files. Playing the media is obviously a different story, but even so I'd wager some dosh on a 1Ghz Athlon being more than enough.

I dropped my dual core Athlon from 2.6 to 1.5GHz to test and noticed no difference in Windows and desktop tasks.

 

[Bleek]

Still dont understand why people care about power consumption..

You're either very young (oblivious) or very old (not willing to conform).

I'm far from being a GreenPeace member but my trading machine needs to be on 24/7.

Thus I want a quiet (read silent), cool running PC. That ultimately means I need low power, the added bonus is I can run it for a few pence a week and not worry about it.

Heat is wasted energy, your power churning PC isn't very effecient, my little AMD is.

 

[Bleek]

£22!!!

I better get underclocking some more to make up for my main/game/leisure rig.

 

[Bleek]

I'm doing it for three reasons, noise, heat and power use.

I like the fact the cpu is currently running at room temp, that's pretty cool (literally).

 

[Bleek]

Hey Ed,

if those figures are accurate and your system is stable then that is an amazing result. I've been tinkering with ULV computing since March 2008 and have never managed to get a system running semi loaded at 25w

The one thing you have done which I never got round too was underclocking the CPU frequency so that may well shave off some extra watts. I'm running an undervolted Stock E5200 @ 1.08vCore and an undervolted stock E8400 @ 0.960vCore with most voltage options dialed down and using laptop 2.5" hard disks that use about 1-2watts.

I managed to halve my CPU watt usage by dropping from 2.6GHz and halved it again going from stock to 0.8v, I'm also using a single laptop drive, no CD rom, under-volted memory and NB with a very efficient 780 AMD chipset. I need to check full load but I estimate around 40watts at max load.

100% load for 10 minutes and the Athlon was still only 37'c and that was in the weekends heat! I'll get my pyrometer on the core to double check it against the probe to be sure.

 

[Bleek]

What is this Madness !!!

Look at my signature, I'm flying the clocking flag too.

 

[Bleek]

I've heard a lot of good things about the AMD 780G but in most of the reviews I read which included power consumption charts seemed to indicate it used more power than the Intel G45 express platform? Your the first person I heard about who has produced a stellar ULV result using the AMD platform!

Also remember I'm using the onboard VGA and I've downgraded that too, running 350MHz instead of 500MHz with reduced volts - again absolutely no performance decrease evident in Windows.

Oh and for software voltage adjustments i.e. to lower further than your BIOS allows take a look a this - http://www.silentpcreview.com/article231-page1.html offers a comprehensive (if not dated) guide to optimizing your computer using CrystalCPUID (freeware).

Using the profile manager (dynamic clockspeed management) in CrystalCPUID, you can also set 3 different clockspeeds and VIDs to allow your computer to scale based on processor load. You can underclock/volt down to minimum at idle, and have it scale up to max power when necessary!

 

[Bleek]

One thing I am not entirely sure about thou is say if I got a quality 500w psu with very high efficiancy like say 80% to 90% does that mean if the components are using say 100w then that is the power it will draw from the socket or would it be much more? I would like to know this.

I'd use the smallest PSU you can get away with (200W in my case) - by their nature they inherently waste less power.

Just stay under the 50% load at peak (of 100% effiency) and you'll keep the PSU nice and cool, wasting even less energy.

 

[Bleek]

Onboard VGA down from 500MHz to 280MHz and 0.9volts, no adverse effects so far. That'll save me a few watts, ha!