HTPC high power usage when OFF

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Freeco
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HTPC high power usage when OFF

Post by Freeco » Tue Oct 26, 2010 11:06 am

Out of curiosity I've put a power meter between the power cord of my new HTPC & the power outlet. I know computers still consume some electricity when they're powered down, that's why I always put a power switch on the outlet. When the computer's off, I simply push the button reducing power consumption to 0.
My other computers use between 3-10W when powered down... Even the very old ones don't use that much. The figure I got from my HTPC was 18W, yes when off :shock: It only consumes 41W when powered on (idle)! Completely rediculous :x
Ok, it's a cheap meter, but it won't be 10W off...

These are the components of my HTPC:
Case: Silverstone Grandia GD04B
PSU: Nexus value 430
Motherboard: MSI H55M-E33
CPU: Intel Core i3 530 2.93GHz dualcore
GPU: integrated in CPU
CPU cooler: Scythe Big Shuriken
RAM: 2x 1GB Kingston DDR3 1333MHz
SSD: Crucial RealSSD C300 64GB
Blu-Ray ROM: Lite-On IHOS104
Fan control: Zalman FanMate 2
Casefans in: 2x Nexus 120mm @ 6V

Is it a problem of the PSU or motherboard? I read in the Nexus review it only draws 0.4W when in standby. The motherboard will also consume some electricity, but as it's a very simple, no-nonsense µATX board it shouldn't be that much. If I'm not mistaken all other components should be completely powered down when the PC is off.
I'm just curious why the number's that high. I'll definatelly remember to use that flipswitch on the power outlet when I'm done watching movies :wink:

HFat
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Re: HTPC high power usage when OFF

Post by HFat » Tue Oct 26, 2010 11:49 am

Check if wake on LAN (or wake on anything really: mouse/keyboard, timer, whatever) is enabled. Disconnect USB devices or see if there's a BIOS option to cut USB power when the computer is off.

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Sun Nov 14, 2010 10:15 am

late reply, but anyhow...

There's only 1 USB device connected and that's the USB receiver for my wireless keyboard. Unplugging it makes no difference to power consumption when powered down.

I don't see anything else that I could disable without losing fuctionality. It's already the minimum I think.
I've made pictures of the most important settings. Don't want to write them all down :wink:

ps: a couple of days ago I've upgraded the BIOS version from v1.8 to 1.9. The release notes didn't mention anything worth while, but did it anyway. I haven't checked power consumption again, but I don't foresee any changes after this simple update.
01_StandardCMOSfeatures.jpg
02_AdvancedBIOSfeatures.jpg
03_IntegratedPeripherals.jpg
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Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Sun Nov 14, 2010 10:18 am

continued...
03-1_OnChipATADevices.jpg
03-2_IOdevices.jpg
04_PowerManagement.jpg
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Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Sun Nov 14, 2010 10:21 am

continued ...
04-1_WakeUpEvent.jpg
05_HWmonitor.jpg
06_GreenPower.jpg
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Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Sun Nov 14, 2010 10:24 am

... finally.
07_CellMenu1-2.jpg
07_CellMenu2-2.jpg
07-1CPUfeature.jpg
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Bobert
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Re: HTPC high power usage when OFF

Post by Bobert » Mon Nov 15, 2010 9:05 pm

Freeco I have the same board and processor with a Corsair VX450 and doing a complete shutdown the computer uses 1 watt from the wall. If using the standby feature it uses 3 watts.

Not sure but could be your mobo or possibly PSU. I have some older PSU's that when shut down use around 4 to 5 watts but they are over 10 years old.

I went through three MSI motherboards. The first mobo I sent back because my monitor would not come on during a cold boot. I only found out after trying 2 other boards that they exhibit the same behavior (eventually the monitor comes on late in the boot process).

The first board would go into standby fine and come out of sleep fine. However the second board I received had major problems going into standby, and would never wake up. If I remember the power usage was quite high during standby but I don't remember how much since I boxed the mobo up for RMA within hours of receiving it and sent it back. I do remember though when the second board was completely shut off, the power usage was 1 watt like the others. The third board which I'm using now works fine for standby and during wake up and uses the power figures I quoted above.

I'd say if your computer uses 18watts when completely shut off it could the the PSU. If it's using 18w during standby though I'd lean towards the mobo.

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 12:51 am

When I have the time this week I'll check power consumption when in standby. I never use that feature, but just to complete the exercise :)

Monkeh16
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Re: HTPC high power usage when OFF

Post by Monkeh16 » Tue Nov 16, 2010 4:57 am

Are you sure your meter isn't displaying apparent power?

andymcca
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Re: HTPC high power usage when OFF

Post by andymcca » Tue Nov 16, 2010 5:45 am

Monkeh16 wrote:Are you sure your meter isn't displaying apparent power?
This

Also, your speakers, monitor/tv, and other devices are not fed through the meter, right? Because it could be your giant speaker system's coils, or a TV with terrible standby efficiency.

Edit: Errr.. Do speakers generally use permanent magnets with no DC coil? I know my crappy small set uses ~5W idle, but I guess that could be electronics.

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 6:50 am

What do you mean with "apparent power". Don't understand that terminology :oops:

ONLY the HTPC was connected to the power meter off coarse! So only the power cable leading to the HTPC power supply.

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Re: HTPC high power usage when OFF

Post by Monkeh16 » Tue Nov 16, 2010 8:27 am


Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 9:27 am

sorry, but I only understand half of that. I know the basics of electricity like P = U * I, from what I learned 10 years ago in highschool in Physics class, but nothing about resistive or reactive loads and stuff like that :wink:

So how can I be sure of what it's reading?
I know this energy meter isn't accurate, as it only cost about €10 so it's el-cheapo material. I don't expect dead-on measurements, but a fair estimate.
On the other hand, I've just now put it between a 9W light source and it reported exactly that. But there aren't any capacitators in a device like that (not that I think... balast?).

So...
New test: in stead of reading the Wattage, I've read the A & V which were 0,08A & 235V. If I do the math myself that's still 18,8W.
And when in standby the usage is identical compared to completely shut down.

andymcca
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Re: HTPC high power usage when OFF

Post by andymcca » Tue Nov 16, 2010 9:53 am

For DC, apparent power and "real power" are the same thing.
P = V * I

For AC, these two are only the same if your voltage wave and your current are timed properly (specifically, 90 degrees difference in the constant B in the equation Vpk * cos(A*t + B), if you remember your trig).

In cases where there is capacitive or inductive quality to the load (such as in power supplies), the angle between the current and the voltage changes, and apparent power (V * I) begins to differ from dissipated power (what you pay for as a home user, at least in the USA). The issue is that some energy is stored and released in the capacitive/inductive load with every cycle, so the current looks larger (in terms of RMS or peak voltage) than you would expect given the heat/acceleration/other "real" uses of energy observed.

So, in summary, your meter can probably give you a value in Watts (W), which is typical for dissipated, or real, power. It can also probably give you a value in Volt-Amps (VA), which, while the same as W if you do some unit analysis, is the standard unit for apparent power.

You only pay for "real" power in most places (although more current on the line may heat up the supplying conductors, adding some minuscule load), so you should only care about the figure in watts (unless you are getting super crazy about things).

EDIT: Since you are straight out multiplying your current and voltage, you are getting apparent power. Does your meter offer you a value in watts? Or can you get phase angles for the current and voltage? Without angles it is impossible to calculate the real load. -Andy

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 10:33 am

I think you're a bit missing the point Andy ;-)
I'm just curious why the same power meter shows me my regular desktop (see signature) draws about 5W when off, as do my other older desktops more or less, while my brand new HTPC consumes 18W when off.
Not that I'm going to RMA the piece that's 'faulting', I use a flip switch on the outlet anyway, a,d everuthing functions perfectly. But it just seems 'odd' this new hardware consumes 3x than usual.

For completeness:
My meter can show W, max W, V, max V, A and max A. I always look at the simple Watt value. I just now calculated V * A, just for the excercise of being accurate.
It also has some other functions like calculating your electricity bill, but it's too complicated to enter the necessary values. I can do the math myself if I want if I how how much something uses over which time frame.
And I checked the spec sheet: minimal A is 0.02A, and there's a 5% error when measuring W while 3% for A & V.
Oh and by the way, maths wasn't a thing for me. Ok, I can do calculations like any other person, but sin/asymptotes and stuff like that didn't interest me one bit. I learned them for the exams, but quickly forgot all of that once no longer needed for school. I don't use stuff like that in my job anyway, so why bother refreshing it...

Monkeh16
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Re: HTPC high power usage when OFF

Post by Monkeh16 » Tue Nov 16, 2010 10:38 am

Perhaps your new PSU has a low power factor in standby.

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 10:54 am

oh, I just remembered I still have an ancient AOpen 235W ATX PSU lying around (yep, I keep everything :roll: Still have my PII somewhere :lol: Even a Pentium mobo in a box :wink: )
It's very old so it only has a 20pin connector, not 20+4 & 4/8pin additional cable (for CPU?), but I think that should be enough to provide the motherboard with some juice for simply being off. I won't be able to boot, and that's not the point.
Just a simple test to compare power draw when off with this other PSU. If it's much less (5-10W as my other desktops), than the motherboard isn't to blame for that, but the Nexus PSU.

Sounds like a good test, doesn't it?
But when will I feel like taking the case out of the cabinet and unplug everything again... :x
Maybe this weekend :wink:

Monkeh16
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Re: HTPC high power usage when OFF

Post by Monkeh16 » Tue Nov 16, 2010 12:01 pm

Sounds like a pointless exercise in discovering a low power factor on standby to me.

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Tue Nov 16, 2010 12:06 pm

I do not use standby... ever...
I always shut the computer down, completely.

I'm just curious why it's still consuming 18W when off. That's my point, nothing else.

Monkeh16
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Re: HTPC high power usage when OFF

Post by Monkeh16 » Tue Nov 16, 2010 12:10 pm

When I say standby I'm referring to the PSU, not the PC.

You cannot completely turn an ATX supply off short of physically disconnecting the supply.

Try disabling that EuP 2013 thing. It may well increase power consumption enough to increase the power factor and reduce the apparent power. Yes, I know that sounds strange.

andymcca
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Re: HTPC high power usage when OFF

Post by andymcca » Tue Nov 16, 2010 1:42 pm

Sorry for the rambling explanation earlier!
Monkeh16 wrote:Perhaps your new PSU has a low power factor in standby.
I agree with this. Your power supply almost definitely is the culprit, unless you have a bunch of USB devices plugged in which are remaining on. (Edit: "almost definitely" may be too strong :) )

I know some supplies used to use a shunt resistor to prevent problems where one of the rails was under-loaded. I'm not sure if they still do this, but perhaps this particular supply is still supplying the shunt(s) while in standby?

PS I think most cheap CFLs not-super-high power factors, so you would be able to see that V * I > P in the case of your lamp. If your meter reports 9W but V * I is higher, then it would appear that your meter is displaying dissipated (real) watts, and we can't blame the power factor of your PSU. (But the above shunt idea may still apply)

:D

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Sat Nov 20, 2010 7:27 am

Pointless or not, I went on with the exercise :wink:
Summerazing power consumption when off in different situations:
* with Nexus Value 430W --> 18W
* with ancient AOpen 235W ATX PSU --> 9W
==> I think we can conclude the problem is the Nexus PSU. But as I already mentioned I'm not going to RMA it as nothing else is wrong with it. I don't even think the RMA would be accepted for this reason.

What really struck me...
On the Nexus there's a on/off switch at the back. Nothing special, right... I always leave it on, as it's too hard to reach. I use a similar switch on the power outlet which is easier to reach.
Now that I had the case out of the cupboard I flipped the switch to its off position thinking the power meter would go back to 0W. Well... no! It still showed 7W. Even when unplugging the cables feeding the motherboard it seems this PSU consumes 7W when off.
Out of curiosity I did the same with the AOpen PSU laying completely loose on the table: 9W. It doesn't have an on/off switch, so this will be it's standby power consumption (more or less).

Making a new summary:
The Nexus PSU consumes 18W in standy mode, while 7W when off. The AOpen consumes 9W in standby and can't be switched off completely.
With these numbers I don't think the motherboard itself draws much power when the computer is shut down. Might be a couple of hundred mW's, which don't really show on my meter.

Yep, I keep on rambling on don't I :wink:
But at least I've learnt some things:
* keep on using the flipswitch on the power outlet when I'm done using computers. If you have a couple of them in the house like I do, that can make a couple of euro's on the electricity bill every year. It would be wasted money anyway.
* a PSU consumes power when in standby (nothing new), but still when completely off (at least my Nexus does).

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Re: HTPC high power usage when OFF

Post by MikeC » Sat Nov 20, 2010 8:08 am

Actually, I think Nexus would and should provide RMA for that PSU. You paid good $ for that PSU and it is not working the way it should be. One of our lab samples had problems going in/out of PC standby -- Nexus agreed this was a fault & worked with us to identify the problem (to prevent it in future).

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Re: HTPC high power usage when OFF

Post by Monkeh16 » Sat Nov 20, 2010 8:16 am

And once again, I'm fairly confident it's not actually using any power.

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Re: HTPC high power usage when OFF

Post by MikeC » Sat Nov 20, 2010 6:15 pm

I wonder, too, about the accuracy of Freeco's power meter, it's too bad he can't provide a link to complete info about it, but that comparison with his ancient 235W PSU suggests the Nexus is at fault. I have my doubts about the basic quality of the Nexus, despite giving it an Editor's Choice -- on the basis of its acoustics and its good enough electrical performance. As I mentioned, we did have trouble with one of 2 samples.

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Re: HTPC high power usage when OFF

Post by Freeco » Sun Nov 21, 2010 2:09 am

guess it's useless to you, but I found to manuals for my power meter on the web:
Dutch: http://www.gebruikershandleiding.com/Ch ... 20802.html
French: http://diplodocs.nl/fullswf-CHACON.php? ... 6&cat=vide

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Re: HTPC high power usage when OFF

Post by andymcca » Mon Nov 22, 2010 8:51 am

Times like these I wish I read dutch :D

Very interesting case, though. I'll dust off my wattstopper p3 in the near future and let you know what my psus do idle and off. Obviously the difference in meter may be an issue hampering comparisons!

It is very suspicious that it did not go to 0W with the switch off, regardless of capacitive load quality, shunts, etc. Says to me there is something wrong with the PSU or the meter :)

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Re: HTPC high power usage when OFF

Post by frenchie » Mon Nov 22, 2010 9:04 am

And if the only thing in the plug is the power meter, it DOES display 0 Watt right ?

Freeco
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Re: HTPC high power usage when OFF

Post by Freeco » Mon Nov 22, 2010 9:46 am

yes, when nothing's connected to the meter the display shows 0W.
Anything below 4W doesn't show, as according to the manual it needs at least 0.02A to detect a current.
That's 4.7W to be exact (0.02A * 235V), but 4 is the lowest that I've ever registered. Maybe it's always rounding down, or it's just due to the 5% error margin. Who will tell...

Btw guys: you can leave it at this. I'm not going further with this. Originally I simply wanted to know whether the PSU or the motherboard was to 'blame', and I guess now we now. I think I'm not going to get a better answer without having a more advanced meter in my house. I don't intent on buying one, and I don't know anybody that has one, so...

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