What is the lowest wattage system you can achieve?

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jones_r
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What is the lowest wattage system you can achieve?

Post by jones_r » Mon Jul 30, 2007 1:20 am

I want to make a server that will be composed of:

1. CPU
2. Motheboard
3. 1 Hard drive

All this server has to do is to download files (under WinXP).

I want it to be as quiet as possible.

Is it possible for such system to idle at *less* than 30 Watts ?, what parts should I be looking at ?

I know that an HD takes about 10W, so this leaves less than 20W for the CPU+Mobo, is this possible ?

Using a Pentium III 500mhz based system (downclocked to 333mhz), I was able to get 48watts at idle, and ~60watts at max consumption, but this is still too high for me...

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Post by Bluefront » Mon Jul 30, 2007 2:15 am

You'll probably need a VIA C3 or C7 board.....some of which are rated less than 10W. Link. For sure you'll need a laptop HD. A normal hard drive draws more than 10W at start-up. That leaves you under 30W.....add a fan or two, maybe a low-power card of some sort, you're still under 30W.

For the usage you suggest....that'll work. A few network drives should give enough storage. Go for it....
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Post by jaganath » Mon Jul 30, 2007 2:54 am

you obviously don't need much CPU horsepower,so AM2 Sempron downclocked to 800Mhz/0.8V should work.

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Post by MikeC » Mon Jul 30, 2007 5:53 am

Here's a VIA C7 mITX system w/ notebook drive that we managed to make idle at 17W and max out at 24W.
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Post by Lawrence Lee » Mon Jul 30, 2007 8:06 am

In my Biostar TF7025-M2 review, I managed to get 34W idle with a X2 3600+ at 1.28Ghz & 0.850V. With a good PSU and a Sempron (you need a 1.8Ghz model or higher to undervolt), 30W is definitely doable.

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Post by Max Slowik » Mon Jul 30, 2007 8:54 am

http://www.gumstix.com/waysmalls.html

Their 400MHz PC at full load draws 220mA @ 4.5V or .99W. Wait, whatdows?
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Post by jones_r » Mon Jul 30, 2007 9:03 am

Here's a VIA C7 mITX system w/ notebook drive that we managed to make idle at 17W and max out at 24W.
Wow, this thing is amazing !!!, silent, low wattage consumption, and relatively capabale.

I wonder though, if I will use a normal 7200rpm desktop hard drive (say 120gig), instead of the notebook one, how much more wattage do you think this will add to the deal ?

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Post by MikeC » Mon Jul 30, 2007 9:43 am

jones_r wrote:
Here's a VIA C7 mITX system w/ notebook drive that we managed to make idle at 17W and max out at 24W.
Wow, this thing is amazing !!!, silent, low wattage consumption, and relatively capabale.

I wonder though, if I will use a normal 7200rpm desktop hard drive (say 120gig), instead of the notebook one, how much more wattage do you think this will add to the deal ?
Check through the HDD reviews. We've mostly measured DC power draw of 3.5" drives at 6~8.5W in idle, and up to 11-12W in seek/write. Add the efficiency loss of a 75~80% PSU and this translates into 8~10W and 13~16W AC. In comparison a laptop drive idles ~1W and almost never exceeds 3W DC. So you'd probably have to add a minimum of ~7W AC in idle and perhaps 10W AC in seek.

Note that WD has announced a new Green Power version of their Caviar drives, and cite 4W idle & 7.5W max for their 1 terabyte drive -- see the specs here.
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Post by jones_r » Mon Jul 30, 2007 12:10 pm

Thanks Mike !,

So, you're saying with a desktop HD, I need to add ~10watts to your 24watts reading, so this will put things around 35watts (at max computer stress!), which is far and beyond what I thought possible.

I will need to hold off with WD's new drive, as this VIA computer is not very cheap.

I have two other questions:
1. Do you think the 80watts picoPSU should be more than enough for the above ? (I still would like to keep a bit of headroom).

2. Do you know what is the difference between the EN12000E that you reviewed, and the EN12000EG ?, does VIA has anything better price/performance wise ? (since it has already been a year since your review).

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Post by MikeC » Mon Jul 30, 2007 1:33 pm

jones_r wrote:Thanks Mike !,

So, you're saying with a desktop HD, I need to add ~10watts to your 24watts reading, so this will put things around 35watts (at max computer stress!), which is far and beyond what I thought possible.

I will need to hold off with WD's new drive, as this VIA computer is not very cheap.

I have two other questions:
1. Do you think the 80watts picoPSU should be more than enough for the above ? (I still would like to keep a bit of headroom).

2. Do you know what is the difference between the EN12000E that you reviewed, and the EN12000EG ?, does VIA has anything better price/performance wise ? (since it has already been a year since your review).
That 35W AC draw would be hard to reach because it means the CPU, GPU and HDD would all have to be at max load simultaneously. It's hard to imagine what real app could make that kind of load!

There are many other VIA / mini-ITX variants. You might want to shop around for one that meets your needs & is cheaper.

Yes, I think the 80W AC/DC brick + picoPSU is enough for any VIA m-ITX + HDD.

3. No. Study the specs, the differences are there.

WD has those green variants starting from 320GB capacity, btw.
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Post by jones_r » Mon Jul 30, 2007 1:57 pm

WD has those green variants starting from 320GB capacity, btw.
I will look into it, thanks.

Btw, something I forgot to ask, in your review of the mini-ITX, there was one thing that scared me, you said that when the CPU was stressed (when merging images, I think), it caused the entire computer to freeze, and the only way to un-freeze was to shut it down.

If the computer is not reliable than it might be a mistake to use it as a file server, that suppose to be turned on 24/7....

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Post by MikeC » Mon Jul 30, 2007 6:22 pm

jones_r wrote:Btw, something I forgot to ask, in your review of the mini-ITX, there was one thing that scared me, you said that when the CPU was stressed (when merging images, I think), it caused the entire computer to freeze, and the only way to un-freeze was to shut it down.

If the computer is not reliable than it might be a mistake to use it as a file server, that suppose to be turned on 24/7....
The experience described in the review is precisely the sum of our experience with the board. That particular function was an issue with our system config. Perhaps swapping out the RAM would have solved some of those issues. IN any case, image merging in Photoshop is hardly something a file server will ever be asked to do...

When we reviewed that board, it had only just been released, the BIOS was an early one. I would suggest that for almost any motherboard, the BIOS later in their life cycle usually makes for better, more stable performance. Perhaps it would be worthwhile to seek out older boards that have been around long enough to have gone through a bunch of BIOS upgrades -- and that board is now old enough? Check VIA's line up -- but know that they are not the only ones making m-ITX boards with VIA CPU/chipset.

PS -- if you're interested I have a really early VIA m-ITX board you could fool around with for cheap. Email me.
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Post by ronrem » Tue Jul 31, 2007 1:48 am

If you can find an AMD geode CPU they are very low power. You may find the only way to get one is with the mobo (usually a Biostar) the 1.4 ghz pulls about 14 w normal with a max a bit over 20w. That's an NX. There's lower power versions too. AMD unfortunately has not really market the Geode toward typical consumers.

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Post by AZBrandon » Tue Jul 31, 2007 11:54 am

My Via system with the 533Mhz Eden processor and 40gb 2.5" hard drive draws 10 watts according to my Kill-A-Watt at idle. Only goes up to around 12-14 watts under load. The downside of course is that the Eden is an extremely low CPU power chip, not just low electrical power. If you want something with good speed, a laptop would probably be the best bet. My laptop draws around 12 watts at idle and 20 watts at load, but probably has 10x the real-world computing power.
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Post by loimlo » Tue Jul 31, 2007 7:52 pm

From a friend's computer

INTEL D201GLY, Celeron M 215
1xDDR2 667 1GB
1xWD 40GB, 3.5'

Idle 25W, full running 31W

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Post by jones_r » Sat Aug 04, 2007 11:53 pm

I've decided against the VIA C7 computer. The performace/cost ratio is too low for me.

I've built a Pentium 3 computer, using a Pentium 3 500mhz CPU (28W TDP), and DFI P2XBL motherboard http://www.anandtech.com/mb/showdoc.aspx?i=249

I run the bus at lower speed, so the Pentium 3 registers as 333mhz.

Powering 2 desktop hard drives, Lan card and a graphic card, I'm getting 45W idle (at WinXP desktop), and 65W at 100% CPU usage (Orthos).

The question I have: can I use the picoPSU 80W version, in order to run this computer ?, on one hand, the 65W value at maximum load will probably go down with the PicoPSU (due to its higher efficiency), but on the other hand, the 80W version of the picoPSU has only 36W at the 12V rail, will it be enough to run my computer ?

Here is a link to the picoPSU 80W version specification manual:
http://resources.mini-box.com/online/PW ... manual.pdf

And a link to the 80W power adaptor:
http://www.mini-box.com/80w-AC-DC-Power ... ategory=13

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Post by MikeC » Sun Aug 05, 2007 12:45 am

It would help to know what PSU you're running, but irrc, P3 boards used the 5V line for CPU power. The 80W rating of the picoPSU is supposed to be DC output, and you're telling us AC input, right? I'm guessing the PSU is a generic one from that era, which means it might get 60% eff. at those power levels. Plus the motherboard doesn't even have the 2x12V aux socket (which came in with the P4), so I think you're safe.
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Post by jones_r » Sun Aug 05, 2007 1:06 am

It would help to know what PSU you're running,
I'm using the PSU that came with the "Calmpc" enclosure that was sold several years ago, as the first fanless system (passive phase change cooling). In order to make sure this is not a very high efficiency PSU, I will power the computer today with a regular cheap PSU, and see if the measurements stay the same.
but irrc, P3 boards used the 5V line for CPU power.
Interesting.
The 80W rating of the picoPSU is supposed to be DC output, and you're telling us AC input, right?


I'm doing the measurements while connecting the PSU to a Kill-A-Watt device http://www.the-gadgeteer.com/review/kil ... tor_review

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Post by loimlo » Sun Aug 05, 2007 1:56 am

jones_r wrote: I'm doing the measurements while connecting the PSU to a Kill-A-Watt device http://www.the-gadgeteer.com/review/kil ... tor_review
Yes, It's AC draw which includes heat loss of DC draw.
You remind me of Celeron 300A oc 450 days, I've used it to download.

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Post by jones_r » Sun Aug 05, 2007 2:21 am

While doing the Pentium 3 power consumption measurements, I've stumbled upon something weird I can't explain: When I got into the bios, I got a 63W reading, which is close to the 65W that I got under max load. This is very far form the 45W idle at WinXP desktop, but I always assumed the power consumption at the bios is similar to idle...

Why on earth does the Bios draw so much energy from the PSU ?

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Post by Bluefront » Sun Aug 05, 2007 3:07 am

This thread is confusing......it started out wanting the lowest possible current draw, trying for under 30w. Definitely achievable.....but at the obvious cost of computing power, and a higher price in dollars.

Now we're up to maybe 65w, using an older P3 system that isn't much faster than the slower VIA boards, while using 2x the current. To me it's plain that the newer VIA boards are relatively expensive, and laptop drives cost more per GB than desktop drives, while drawing far less current.

So it boils down to just how much are you willing to spend to achieve a very low current draw? And at the same time......how much performance are you also willing to sacrifice to achieve that low-power computer.

I have a VIA 733mhz setup with one used laptop drive, and some old memory sticks from a junk-pile. The case was new, cost $50 w/80w psu. I've got $150 in this very low-power computer. If I put a PICO in it, it would draw even less power.....maybe under 30w. Now I know it's not very fast......but it's fast enough, and cheap enough, and "green" enough. You can't have everything with this sort of computer. You have to make sacrifices.....
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Post by jones_r » Sun Aug 05, 2007 3:50 am

This thread is confusing......it started out wanting the lowest possible current draw, trying for under 30w. Definitely achievable.....but at the obvious cost of computing power, and a higher price in dollars.
Yes, I've changed my mind.
Now we're up to maybe 65w, using an older P3 system that isn't much faster than the slower VIA boards, while using 2x the current.
Remember, I use 2 desktop HDs, if I change it to 1 laptop HD, I can reduce maybe 15W, and be at 50W under max load.

Regarding the speed of the VIA in relation to the P3 system, a much more important thing for me than speed, is stability. The Pentium 3 is rock solid, while the VIA has issues under max stress.

I already had all the parts for the Pentium 3 computer laying arround, so it cost me nothing. I simply don't feel the urge to go spend ~$200 for a system I'm not even sure will meet my needs (stability wise).

I feel like by going with the Pentium 3 system instead of the VIA system, I'm loosing practically nothing.
You can't have everything with this sort of computer. You have to make sacrifices.....
Yes, and I sacrified some wattage in order to get a perfectly stable machine.

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Post by loimlo » Sun Aug 05, 2007 6:54 am

Hey, I've a VIA EPIA downloading without an error. :wink: What stability problem do you encounter? I don't think any VIA processors above 1Ghz wouldn't compete against P3 533. Even my oldest C3 533 is enough to download.

But I agree with your thoughts. P3 is "green computing" enough, anything below 50W, and you pay nothing for decent power-saving.

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Post by mb2 » Sun Aug 05, 2007 7:34 am

if this p3 happens to be a socket 370, consider swapping it out for a celeron 533-600mhz, 1.5V. they are 11w, which is a significant saving over the P3 for not really any significant cpu power loss, and equal stability.
oh and they are practically free on ebay.
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Post by MikeC » Sun Aug 05, 2007 8:46 am

IMO, this P3 is fine for what you're doing, and reusing old parts is greener than buying anything new. The primary power inefficiencies come from the fact of 3 HDDs and the inefficient PSU; yes, I am familiar with the PSU in the Calm case you mention -- it was mediocre then and worse by today's standards. If you consolidated the HDDs into a large one, perhaps one of those new energy-efficient WDs, and replaced the PSU with a more efficient one, you could easily get <50W at load.
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Post by VanWaGuy » Sun Aug 05, 2007 9:35 am

Hi Jones_r,

A co-worker and I were talking about the probable cause of the BIOS idle vs. Windows apparent idle power discrepency.

Most BIOS's will not use the halt instruction, and so even when not doing productive work, the CPU is still busy the whole time. (And it was not that long ago that people used third party programs (Rain, Waterfall, CPU IDLE) to accomplish that under Windows. I think use of halt came into Windows in NT and 2000.)

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Post by truckman » Sun Aug 05, 2007 9:43 am

I've got a 1 GHz Via C3 CPU in an ordinary socket 370 motherboard. There are three randomly chosen LAN cards installed, and the graphics card was the one from my junkbox that gave the lowest system power consumption. The hard drive is a 2.5" laptop drive. The power supply is a 300W Seasonic Super Tornado. Power consumption at idle is 35W.

I suspect the power consumption would drop quite a bit if I only had one LAN card in the system or if I replaced the Seasonic with a picoPSU.

If your motherboard is compatible with the Tualatin P3 CPUs, then you buy a cheap Nehemiah-core C3 (11W typical) off Ebay. If your board is older, than you could get an one of the older, slower, and cheaper versions of the C3. I just stumbled across this info about the Via C3 product line.

I've got a Hitachi 7K160 3.5" 160GB drive in one of my newer systems here. The PATA version is spec'ed to idle at 5W.[/url]

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Post by jones_r » Sun Aug 05, 2007 1:10 pm

Thanks for all the advice, guys.
if this p3 happens to be a socket 370, consider swapping it out for a celeron 533-600mhz, 1.5V. they are 11w
Nope, it's socket 1. It's easier to cool though, since the heatsink is pretty large.
yes, I am familiar with the PSU in the Calm case you mention -- it was mediocre then and worse by today's standards.
You are correct. I did the measurements again today, using a cheap chinese PSU, and got ~2W more than with the Calmpc PSU. This means that the Calmpc PSU is also around 60% efficiency, so, if I'm getting now 65W at max load with 60% efficiency, then with the picoPSU I'll get less then 50W at max load, without doing anything else.


VanWaGuy,
What you say about the "halt" command makes a lot of sense, thanks.

truckman,
Do you really think that those LAN cards are the fault ?, When I switch off my LAN card, I can barelly see a difference on the WAT meter, it takes no more than 1W, I think.

Do any of you know if computers from the Pentium 3 era should have problem accepting PCI cards that are made today ?, I tried to install a USB2 PCI card, and the computer did not boot. I will try a firewire PCI card tomorrow. If that won't work too, then I'm in a trouble, since I can't share files rapidly enough (the pentium 3 has USB1.1 which is slower than my internet connection, and for some reason I'm getting only 3-4 MB/sec with the network card). I know that the P2XBL motherboard I'm using with the P3 has PCI v2.1 slots, maybe all the cards made today are for v2.2 PCI slots, and this is the reason it doesn't work ?, I hope not.

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Post by MikeC » Sun Aug 05, 2007 1:16 pm

jones_r wrote:Do any of you know if computers from the Pentium 3 era should have problem accepting PCI cards that are made today ?, I tried to install a USB2 PCI card, and the computer did not boot. I will try a firewire PCI card tomorrow. If that won't work too, then I'm in a trouble, since I can't share files rapidly enough (the pentium 3 has USB1.1 which is slower than my internet connection, and for some reason I'm getting only 3-4 MB/sec with the network card).
Yeah, this kind of thing is often a problem with older gear. My wife's home PC is a P3-Tualatin I built maybe 5 years ago. I try not to change it in any way to avoid incompatibility hassles. You should certainly get better than 3-4 MB/sec w/the NC. You'll probably have to try different ones -- both NCs and PCI/USB2.
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Post by truckman » Sun Aug 05, 2007 1:24 pm

jones_r wrote:truckman,
Do you really think that those LAN cards are the fault ?, When I switch off my LAN card, I can barelly see a difference on the WAT meter, it takes no more than 1W, I think.
I'm not absolutely certain because I haven't actually tried removing all the cards, but at least one of them is ancient and probably consumes more power than more modern cards. Other than that, I can't think of a reason for this system to draw even 35W.

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