Reading the electric kibble thread made me check my watt meter I had plugged in and forgotten. That in turn made me think of this thread.

Question: how many watts is your rig burning?

In my case, this one http://setiathome.berkeley.edu/show_host_detail.php?hostid=5336154 is going at 700 [edit]-800 [/edit] watts presently.

Post your rig link and its wattage for some interesting comparisons.

Regards,

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I do not have a wattmeter tho I do get a bill at the end of the month.

However, I do have gpu-z and it looks like I am drawing between 21 and 41 amps while crunching seti. I recall milkyway gave a higher average like 32 - 40. Collatx did not pull as much as milkway I think.



The above current is for my gtx280 with its 64nm core size. I would be interested in what your gtx285's are drawing as they have a smaller die.

Not all nvidias have current sensors. I cant get a valid reading on a gts250 or a 9800gtx+

Trying the new version released today it doesn't look like it supports 285's yet (in the release notes they're up to 280's so there's hope!). I don't get all the VDDC readings that yours does. In particular, nothing about the amps.

Interesting reading nevertheless. I was at first surprised to see the amperage reading. It took me a moment to remember that the voltage on the rail is 12, ergo the amps it is pushing isn't as significant (it took me a moment to reconcile that the typical wall socket is giving you 15 amps in North America but at 120 volts - I'm plugged into a 20 amp circuit I put in for a table saw originally).

Doing some Googling the 280 can ramp up to 236 watts at load. Conversely the reviews say the 285 runs at a reduced wattage of around 183 at full load (apparently only 1 watt more than the 260) - not that I knew until this moment.

They also talk about the GPU running up in stages as demand requires. I've seen this watching the EVGA Precision tool as CUDA WUs come and go and the GPUs run up and back down again in speed.

Here's a link to a comparison (not much use to both you and in a fashion given we'd made our choices without it in the first place!): http://www.firingsquad.com/hardware/evga_geforce_gtx_285_ssc_performance_review/

Regards,

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I scrolled the screen down to where the gpu voltage is displayed and wrote the image back out. It is only 1.1 or so volts, not 12. Hit CTRL-F5 if in IE to refresh the gpu-z image. So about 1.1 * 40 amps = just over 44 watts peak. 40 amps * 12 would be too high a wattage and that made me go back and re-examine gpu-z I assume there is significent efficiency loss converting from 12 down to 1.1. I am no engineer but I know ohms law. Since this unit is used only for boinc then the video load is 0.0 and I assume the current requirement is much more if gaming.

To convert from high to low Voltage modern computer circuits use:

Switched-mode power supply
http://en.wikipedia.org/wiki/Switching_power_supply

"
A linear regulator maintains the desired output voltage by dissipating excess power in ohmic losses (e.g., in a resistor or in the collector–emitter region of a pass transistor in its active mode).
A linear regulator regulates either output voltage or current by dissipating the excess electric power in the form of heat, and hence its maximum power efficiency is voltage-out/voltage-in since the volt difference is wasted.

In contrast, a switched-mode power supply regulates either output voltage or current by switching ideal storage elements, like inductors and capacitors, into and out of different electrical configurations.
Ideal switching elements (e.g., transistors operated outside of their active mode) have no resistance when "closed" and carry no current when "open", and so the converters can theoretically operate with 100% efficiency (i.e., all input power is delivered to the load;
no power is wasted as dissipated heat).
"

.

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- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

I scrolled the screen down to where the gpu voltage is displayed

That's where I was a bit puzzled. In my effort I didn't get something I could scroll, just one complete image, minus the VDDC info.

Although the GPU runs at a low voltage, the card itself is sitting on a 12 volt rail that is also utilized to run the fan, and various other bits and bytes round on the board itself. Good point however that the GPU's voltage is likely the one being described in this case.

BilBg is definitley more of an electronics whiz that I. I've now learned some of the source for all that heat!

As I was building the box I had the watt meter on throughout. I wasn't sure if a 1000 watt PS would be sufficient. With no GPUs onboard I was clocking in the 250-300's (a colleague was ribbing me that his build being done at the same time for another purpose barely used enough to light a bulb in comparison). As each of the three GPUs went in I saw the complementary increases in power use: 400-550, then 550 - 700, now 700 - 800+. A few additional fans have also been addded since and I think I saw a peak of 890 even at one point when the sides were all on.

Regards,

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You may find this links interesting:

VDDC Current ?
http://forums.techpowerup.com/showthread.php?t=68526

Power Consumption of Contemporary Graphics Cards
http://www.xbitlabs.com/articles/video/display/gpu-power-consumption-2010_3.html#sect0

.

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- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

You may find this links interesting:

VDDC Current ?
http://forums.techpowerup.com/showthread.php?t=68526

Power Consumption of Contemporary Graphics Cards
http://www.xbitlabs.com/articles/video/display/gpu-power-consumption-2010_3.html#sect0

.

Thanks for that link on power consumption. I had been looking for something like that.

To convert from high to low Voltage modern computer circuits use:

Switched-mode power supply
http://en.wikipedia.org/wiki/Switching_power_supply

"
A linear regulator maintains the desired output voltage by dissipating excess power <snip>

In contrast, a switched-mode power supply regulates either output voltage or current by switching ideal storage elements, like inductors and capacitors, into and out of different electrical configurations.
Ideal switching elements (e.g., transistors operated outside of their active mode) have no resistance when "closed" and carry no current when "open", and so the converters can theoretically operate with 100% efficiency (i.e., all input power is delivered to the load;
no power is wasted as dissipated heat).
"

.

ROFL.

BilBg, thanks for pointing people at explanation, it has helped people understand & please take note that what I say is not aimed at you & your helpful post so don't take offence but this is an example of how Wiki P can be amusing.

I like the idea of using "ideal storage elements", in other words perfect transistors, capacitors and inductors that exhibit no resistance. If anybody has a draw full of these components I would love to take them off your hands! I think maybe I should update that SMPS item in Wikipedia to introduce a bit of real world to it.

In case anybody is interested, there must be losses in the real world outside the head of whoever wrote that article :) There are resistances involved in inductors that carry large currents and also in capacitors and PCB tracks that likewise carry large currents. The resistances are small but significant. There are also losses in switches (ie transistors) and diodes. Cutting what could be 100,000 words to a few: switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one.

Looking at an example that you will all be familiar with, the PSU in all your PCs is a SMPS. It is the only really practical way to get large powers or decent efficiencies, in other words CHEAP: both to build and to run. If you look at the spec for your PSU you may be lucky enough to see an efficiency figure quoted - they often don't say. You will probably find it is approximately 80%. Just put your hand on this SMPS and feel the heat that is being generated. An 80% efficient 500W output PSU would require 625W input power - the difference of 125W is dissipated almost totally as heat. Some power is also lost in driving the PSU fan (unless you have a passively cooled one!) which is there primarily to remove the waste heat from the PSU...... I do like Wikipedia but it can be VERY misleading!

The small point-of-use SMPS on a motherboard or GPU could be low to middle 90's. Ones I design usually come out 85% to 95% efficient depending on detailed requirement.

All in all, SMPS allow DC to be treated in a similar way to AC & a transformer. The power out is the efficiency times the power input:

Pout = Efficiency * Pin

This does give MUCH better efficiencies than linear regulators especially where the output voltage is much lower than the input voltage. They also allow the output voltage to be higher than the input which is incredibly useful at times or for the polarity to be reversed. Isolation between the input & output can also be achieved, this is very useful (necessary even) in your PC power supply.

Anyway, I'm starting to whitter off on one! If anyone is really interested I can point you at real manufacturers' IC datasheets and even free simulator software - that is for simulating/designing SMPS NOT flying a plane :) National Semiconductor, Texas Instruments and Linear Technology make most of the devices we use in SMPS.

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

---

 


- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

I agree with everything Odan says, except to say as one who also used to design power supplies. (Now retired) That in the right circumstances linear power supplies can be efficient. I did one where the input supply and the load were stable that was over 85% efficient.

But those circumstances are very rare, and when linear power supplies have to be used in real word situations and the customer requires the output to be within all limits, at all output loads with a supply variation of +/- 15% the 50% efficiency would be regard as very good.

I have done a linear replacement PSU for PC's, because stray emissions below 100KHz caused problems. Can't remember the efficiency but it weighed over 25lbs and took up all the space from front to back of the case. Luckily they used a SCSI external CD.

I have also done DC/DC converters that were below 50% efficient because the supply had to withstand massive input spikes, 50kV on a nominal 100V DC supply. The equipment had to start if the input was as low as 48V and the ambient temperature was -20C. The power supply load was split between the electronics regulated 24V 1 amp, and an unregulated nominal 24V, but below 28V, where the load was >50 amp 1 msec pulses every 10 msec.

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

But in their description of the Buck regulator they say up to 95% efficient.

The buck regulator is the simplest step down SMPS, but is as far as I am aware, only used for battery chargers.

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.

It isn't just resistance, it's also speed.

A switching power supply has a transistor that is being switched between two saturated states (low impedance, nearly zero ohms, and high impedance, nearly infinite ohms) and the heat produced (energy consumed) is pretty low in those states.

... but it takes time, and while the transistor is moving from fully on to fully off, current is flowing through a resistance and that's where you get the heat.

The same phenomenon in the CPU (and every other part) is where the power is used, and heat produced.

If we could build a whole computer using BilBg's ideal components, the entire system would draw no power (and at a nearly infinite clock speed).

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If we could build a whole computer using BilBg's ideal components, the entire system would draw no power (and at a nearly infinite clock speed).

This makes me think of the quest for room temperature super conductors. I can imagine a powerfull CPU that produces no heat because of no resistance, and therefore wouldn't even need a heat sink. I have also been wondering if they will ever make a CPU with fiberoptics and lasers. Even if Moore's law becomes dormant, light would vastly speed up calculations.

---

Warning, addicted to SETI crunching!
Crunching as a member of GPU Users Group.
GPUUG Website

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

But in their description of the Buck regulator they say up to 95% efficient.

The buck regulator is the simplest step down SMPS, but is as far as I am aware, only used for battery chargers.

Buck regulators are very common in modern electronics. In our case, we run a 5 volt back plane to remain compatible with boards that run the 68000 and 68030 processors. In the last processor selection we went to the Motorola Cold Fire processor that was not available in a 5 volt version. We didn't want to change the back plane because we will always have cases where we will need to mix 5 volt boards with the newer processor, so instead we decided to provide a local 3 volt power source on the board for the processor and it's support logic that required the lower voltage. We selected and constructed two designs on the board, because we weren't sure how much power we would require, but the one we populated used this part. This is only one of many parts available for this use.

---

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

But in their description of the Buck regulator they say up to 95% efficient.

The buck regulator is the simplest step down SMPS, but is as far as I am aware, only used for battery chargers.

Responding to 2 at once, versatile eh :)

Yes, that's right. Linear regs can be efficient if Vin is ratiometrically close to Vout. For instance I still use many linear regs for things like generating 3V3 from 5V at low currents, typically <100mA. In that case the 3.3/5 * 100% = 66%. Not wonderful but it is only 1.7V * 0.1A = 0.17 W dissipated at heat - easy to get rid of. The devices are very cheap, very simple, very reliable, and electrically very quiet.

if you are designing a mains to DC supply you use a transformer to get the voltage into the regulator as low as you can for efficiency's sake & as high as you must to make it work reliably with varying input voltages - or indeed at all!

Buck regulators are the primary step down regulator I use for all sorts of things: supplying microprocessors, displays, even complex microwave circuits. They certainly get more use than battery charging. As far as point of use regulation is concerned, I believe the Buck is the main contender. Off-line PSUs, like a PC power supply, use different topologies like "fly-back" and other more complex designs than a buck that use transformers, often for isolation, are very common. Interestingly (at least to me) most battery charging that I do or see is powered by mains power & would use something more complex than a buck. Again a good example would be the PSU for a notebook PC.

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

But in their description of the Buck regulator they say up to 95% efficient.

The buck regulator is the simplest step down SMPS, but is as far as I am aware, only used for battery chargers.

Buck regulators are very common in modern electronics. In our case, we run a 5 volt back plane to remain compatible with boards that run the 68000 and 68030 processors. In the last processor selection we went to the Motorola Cold Fire processor that was not available in a 5 volt version. We didn't want to change the back plane because we will always have cases where we will need to mix 5 volt boards with the newer processor, so instead we decided to provide a local 3 volt power source on the board for the processor and it's support logic that required the lower voltage. We selected and constructed two designs on the board, because we weren't sure how much power we would require, but the one we populated used this part. This is only one of many parts available for this use.

Hey, yes I remember those beasts. Work very well. We tend to use higher switch frequencies these days so we can shrink the footprint & use ceramic caps for size and reliability. An example here bit smaller current but nice part.
We use several of these on a single card to produce different voltages to feed various circuits all powered from a 24V bus. Handy way to do it: cheap, small & efficient as well as reliable.

"switch mode power supplies (SMPS) range in efficiencies about 75% for a "bad one" to 95% for a good one":
Yes - it is like Ideal gas (theoretical approximation) vs Real gas

wikipedia article says:
"so the converters can theoretically operate with 100% efficiency"

Of course there will be losses as you pointed out as the elements are nor ideal and have resistance.
And efficiency of 80% (using SMPS) is much better than if a linear regulator was used for the above discussed GPU:

1.2 V / 12 V = 0.1 = 10% efficiency (if linear regulator was used)


About 15 years ago I had a mainboard (unstable Jamicon used with AMD K5) with linear regulator + two small 3x2x1 cm heatsinks
to power CPU by 3.52 V from 5 V line (only (5-3.5)/5 = 0.3 = 30% lower out-voltage) and the heatsinks become very hot.

But in their description of the Buck regulator they say up to 95% efficient.

The buck regulator is the simplest step down SMPS, but is as far as I am aware, only used for battery chargers.

Buck regulators are very common in modern electronics. In our case, we run a 5 volt back plane to remain compatible with boards that run the 68000 and 68030 processors. In the last processor selection we went to the Motorola Cold Fire processor that was not available in a 5 volt version. We didn't want to change the back plane because we will always have cases where we will need to mix 5 volt boards with the newer processor, so instead we decided to provide a local 3 volt power source on the board for the processor and it's support logic that required the lower voltage. We selected and constructed two designs on the board, because we weren't sure how much power we would require, but the one we populated used this part. This is only one of many parts available for this use.

Hey, yes I remember those beasts. Work very well. We tend to use higher switch frequencies these days so we can shrink the footprint & use ceramic caps for size and reliability. An example here bit smaller current but nice part.
We use several of these on a single card to produce different voltages to feed various circuits all powered from a 24V bus. Handy way to do it: cheap, small & efficient as well as reliable.

We selected our board size early in the 68000 days and had issues getting all the pars on the board. Now days we are still using the same 13.5x13.5 inch board and have combined functions that would have taken 4 boards in the old days on one current board. We populate the board according to need but often leave large sections unpopulated. For us, getting that last little bit of board space is not an issue any longer but the cost of doing a new board is. For us, the most important part is large scale programmable logic. We have a large amount of digital logic that gets sucked up into these parts greatly reducing our space issues.

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This seems like a good time for a theoretical question (slight tangent). Does running your computer, in the winter, add to your overall electricity costs, or not? (let's assume that a person is using 100% electric heat, so we factor out the difference in heating costs of electricity vs. other means) So I guess the question boils down to whether electricity taken from the wall by a computer equals the same cost of heating as an electric heater of equal wattage, or does the fact that a computer is "doing work", ie, crunching workunits, use up electricity in doing those work units?? It's not like a computer is doing "real" work, like we're not all using our computers to grind metal into metal filings or anything like that. What do people think?

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In winter or summer, your computer is like a electric space heater. Almost all of the power going into it is converted to heat just like a space heater. The exception is that some of the power leaves the computer over communication links so it's not 100% converted to heat. If you disconnect the computer form the outside world, then it is 100%. A heat pump would be a better way of doing electric heat because it is moving heat instead of producing it from power. If you are not using a heat pump, then your cost would be the same.

On the other hand, if you are always going to crunch, then you are reusing the power for crunching and heating your house. Heat that would normally be thrown away is put to work for a useful function. The same could be applied to your TV set or Stereo. Our condo is well insulated and has gas heat however between solar input and the power we use, the gas heat is used very little.

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