Got me a Kill-a-watt and some 7970's.....

[yochdog]

Finally made the plunge on a Killawatt....what fun!

I don't know if this is unprecedented, but I was able to overclock AND undervolt 2 of my 7970's and drop the power consumption by a huge amount.

my settings:

Core voltage:  1060
Clock:  1125
Mem:  685

This was pretty stunning to me, but I am getting 1300+ MH/s @ 300+- watts.

4.33 MH/watt.

Now I realize this is not impressive when compared to massively undevolted and underclocked GPU's, but this is a massively OVERCLOCKED set-up!  As a bonus the temps droppe a good 5 degrees with the same fan speed.

Just throwing it out there.....I was pretty thrilled.  I will report back if it stays stable for 24 hours. 

 

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[Cablez]

That is pretty impressive work yochdog!!     I can't wait to hear if remains stable,  gives the 5970 a run for its money as top dog. 

[waterboyserver]

Finally made the plunge on a Killawatt....what fun!

I don't know if this is unprecedented, but I was able to overclock AND undervolt 2 of my 7970's and drop the power consumption by a huge amount.

my settings:

Core voltage:  1060
Clock:  1125
Mem:  685

This was pretty stunning to me, but I am getting 1300+ MH/s @ 300+- watts.

4.33 MH/watt.

Now I realize this is not impressive when compared to massively undevolted and underclocked GPU's, but this is a massively OVERCLOCKED set-up!  As a bonus the temps droppe a good 5 degrees with the same fan speed.

Just throwing it out there.....I was pretty thrilled.  I will report back if it stays stable for 24 hours.  

 

That is a pretty good spot to hash at, are you air cooling? It will most likely be stable at that speed. Anything higher than 1125 MHz will increase wattage significantly, voltage will only need to be changed at ~1240MHz (~200 watts).  How did you decrease RAM clock, was it through driver?

[yochdog]

Finally made the plunge on a Killawatt....what fun!

I don't know if this is unprecedented, but I was able to overclock AND undervolt 2 of my 7970's and drop the power consumption by a huge amount.

my settings:

Core voltage:  1060
Clock:  1125
Mem:  685

This was pretty stunning to me, but I am getting 1300+ MH/s @ 300+- watts.

4.33 MH/watt.

Now I realize this is not impressive when compared to massively undevolted and underclocked GPU's, but this is a massively OVERCLOCKED set-up!  As a bonus the temps droppe a good 5 degrees with the same fan speed.

Just throwing it out there.....I was pretty thrilled.  I will report back if it stays stable for 24 hours.  

 

That is a pretty good spot to hash at, are you air cooling? It will most likely be stable at that speed. Anything higher than 1125 MHz will increase wattage significantly, voltage will only need to be changed at ~1240MHz (~200 watts).  How did you decrease RAM clock, was it through driver?

Yes, air cooling with a small external fan blowing on them as well.

I decreased Mem clock using Afterburner beta 12.....it is the only tool I can get to clock it that low. 

[waterboyserver]

Huh that is interesting, I could never get RAM below 1100, is 685 what Afterburner shows, does GPU-Z sensor readings indicate that same speed?

Finally made the plunge on a Killawatt....what fun!

I don't know if this is unprecedented, but I was able to overclock AND undervolt 2 of my 7970's and drop the power consumption by a huge amount.

my settings:

Core voltage:  1060
Clock:  1125
Mem:  685

This was pretty stunning to me, but I am getting 1300+ MH/s @ 300+- watts.

4.33 MH/watt.

Now I realize this is not impressive when compared to massively undevolted and underclocked GPU's, but this is a massively OVERCLOCKED set-up!  As a bonus the temps droppe a good 5 degrees with the same fan speed.

Just throwing it out there.....I was pretty thrilled.  I will report back if it stays stable for 24 hours.  

 

That is a pretty good spot to hash at, are you air cooling? It will most likely be stable at that speed. Anything higher than 1125 MHz will increase wattage significantly, voltage will only need to be changed at ~1240MHz (~200 watts).  How did you decrease RAM clock, was it through driver?

Yes, air cooling with a small external fan blowing on them as well.

I decreased Mem clock using Afterburner beta 12.....it is the only tool I can get to clock it that low. 

[sveetsnelda]

Something is most definitely wrong with your meter or your math, my friend.  At that clock/voltage, you should be drawing a bit over 200 watts per card (at the wall).  I have three 7970 rigs and they all draw more power at a lower core clock, lower voltage, and a lower memory clock.  To top it off, they don't have hard drives either.  Hell, my water cooled 7970 rig would draw more power than this.  In fact... 

I tried to get as close to that clock/voltage as possible (my cards aren't stable at that core/voltage combo).  With your same settings but 25 Mhz lower on the core clock, I've got 512 Watts total system power consumption with 2 cards.  Granted, this is on a machine with an i7 930, but this measurement was done with no CPU overclocking.  All components (including the GPUs) are water cooled.

Even if you're just trying to calculate the power draw of the GPUs themselves, your measurement is off somewhere.  My pump draws 9 watts.  My idle CPU, board, SSD, and a few power controlled fans aren't going to suck up 212 watts.

[rjk]

Something is most definitely wrong with your meter or your math, my friend.  At that clock/voltage, you should be drawing a bit over 200 watts per card (at the wall).  I have three 7970 rigs and they all draw more power at a lower core clock, lower voltage, and a lower memory clock.  To top it off, they don't have hard drives either.  Hell, my water cooled 7970 rig would draw more power than this.  In fact... 

I tried to get as close to that clock/voltage as possible (my cards aren't stable at that core/voltage combo).  With your same settings but 25 Mhz lower on the core clock, I've got 512 Watts total system power consumption with 2 cards.  Granted, this is on a machine with an i7 930, but this measurement was done with no CPU overclocking.  All components (including the GPUs) are water cooled.

Even if you're just trying to calculate the power draw of the GPUs themselves, your measurement is off somewhere.  My pump draws 9 watts.  My idle CPU, board, SSD, and a few power controlled fans aren't going to suck up 212 watts.

Hmm, maybe it is 2 separate rigs with 1 7970 each?

[sveetsnelda]

I decreased Mem clock using Afterburner beta 12.....it is the only tool I can get to clock it that low.

The oldest beta that was out when the 7970s were released would clock the memory lower.  They put a date limit in the code though, so it doesn't run anymore.  The newest beta will take the memclock lower than 685 when it's first installed (while it complains about needing a restart).  After a restart though, 685 is the lowest.  A BIOS flash is the surefire way to go.

[waterboyserver]

I ran a WC 7970 and a 6850 together, both pull close to 500 watts under a heavy overclock, 300 watts is too low to be true for two 7970's. Sensor readings on 7970 show core around 210 watts with memory around 30 watts; thus actual cards are pulling in well over 200 watts. I get around 3.75 MH/W.

Something is most definitely wrong with your meter or your math, my friend.  At that clock/voltage, you should be drawing a bit over 200 watts per card (at the wall).  I have three 7970 rigs and they all draw more power at a lower core clock, lower voltage, and a lower memory clock.  To top it off, they don't have hard drives either.  Hell, my water cooled 7970 rig would draw more power than this.  In fact... 

I tried to get as close to that clock/voltage as possible (my cards aren't stable at that core/voltage combo).  With your same settings but 25 Mhz lower on the core clock, I've got 512 Watts total system power consumption with 2 cards.  Granted, this is on a machine with an i7 930, but this measurement was done with no CPU overclocking.  All components (including the GPUs) are water cooled.

Even if you're just trying to calculate the power draw of the GPUs themselves, your measurement is off somewhere.  My pump draws 9 watts.  My idle CPU, board, SSD, and a few power controlled fans aren't going to suck up 212 watts.

[yochdog]

Something is most definitely wrong with your meter or your math, my friend.  At that clock/voltage, you should be drawing a bit over 200 watts per card (at the wall).  I have three 7970 rigs and they all draw more power at a lower core clock, lower voltage, and a lower memory clock.  To top it off, they don't have hard drives either.  Hell, my water cooled 7970 rig would draw more power than this.  In fact... 

I tried to get as close to that clock/voltage as possible (my cards aren't stable at that core/voltage combo).  With your same settings but 25 Mhz lower on the core clock, I've got 512 Watts total system power consumption with 2 cards.  Granted, this is on a machine with an i7 930, but this measurement was done with no CPU overclocking.  All components (including the GPUs) are water cooled.

Even if you're just trying to calculate the power draw of the GPUs themselves, your measurement is off somewhere.  My pump draws 9 watts.  My idle CPU, board, SSD, and a few power controlled fans aren't going to suck up 212 watts.

hmmmm, I will slap the Killawatt back on it and re-check the readings.

Perhaps I screwed something up, but I thought I was right on. 

[sveetsnelda]

Perhaps I screwed something up, but I thought I was right on.

Actually, I'm starting to wonder myself now.  Looking at the "VDDC In" stat in GPU-Z is showing a value closer to what you measured.  Because of AC/DC conversion in the PSU, we can tack on some extra Watts due to lost efficiency.

I have a 4x FC HBA in this machine right now and I forgot about it because I was only using it to test something the other day...  Apparently this thing is using a fairly absurd amount of power?  That aside, it doesn't really explain what's going on with my dedicated rig.

More testing.  BRB. 

[yochdog]

Something is most definitely wrong with your meter or your math, my friend.  At that clock/voltage, you should be drawing a bit over 200 watts per card (at the wall).  I have three 7970 rigs and they all draw more power at a lower core clock, lower voltage, and a lower memory clock.  To top it off, they don't have hard drives either.  Hell, my water cooled 7970 rig would draw more power than this.  In fact... 

I tried to get as close to that clock/voltage as possible (my cards aren't stable at that core/voltage combo).  With your same settings but 25 Mhz lower on the core clock, I've got 512 Watts total system power consumption with 2 cards.  Granted, this is on a machine with an i7 930, but this measurement was done with no CPU overclocking.  All components (including the GPUs) are water cooled.

Even if you're just trying to calculate the power draw of the GPUs themselves, your measurement is off somewhere.  My pump draws 9 watts.  My idle CPU, board, SSD, and a few power controlled fans aren't going to suck up 212 watts.

hmmmm, I will slap the Killawatt back on it and re-check the readings.

Perhaps I screwed something up, but I thought I was right on. 

*sigh*......

Alright, I went and re-measured the numbers.  I think what happened was I screwed up the idle wattage the first time around.  Here are the correct numbers:

System idle:  154
Mining with above settings:  512
Hash rate:  1340 MH/s

Soooo, I am getting 3.74 MH/watt.

I am bummed I was not getting what I thought....but still thrilled to shave subsantial power usage.  

[yochdog]

I think I can get close to 4.00 MH/watt, but the system would have to be a dedicated miner.  Using other applications causes instability at lower voltages than the 1.08,

[Roadhog2k5]

I think I can get close to 4.00 MH/watt, but the system would have to be a dedicated miner.  Using other applications causes instability at lower voltages than the 1.08,

so like 180 watts a card. not bad.

[Cablez]

Even at close to 4Mh/W it is real impressive.    Nice

[mrb]

Alright, I went and re-measured the numbers.  I think what happened was I screwed up the idle wattage the first time around.  Here are the correct numbers:

System idle:  154
Mining with above settings:  512
Hash rate:  1340 MH/s

Soooo, I am getting 3.74 MH/watt.

No. It is nonsense to compute the efficiency as 1340/(512-154) = 3.74 Mh/J...
For example, if the cards' idle power consumption would be worse and would be making the machine idle at 350 Watt, would you conclude it would raise efficiency to 1340/(512-350) = 8.27 Mh/J ? Of course not!

You are in fact getting 1340/512 = 2.62 Mh/J which is in line with what I have measured on my own HD 7970 machines.

[chiropteran]

No. It is nonsense to compute the efficiency as 1340/(512-154) = 3.74 Mh/J...
For example, if the cards' idle power consumption would be worse and would be making the machine idle at 350 Watt, would you conclude it would raise efficiency to 1340/(512-350) = 8.27 Mh/J ? Of course not!

You are in fact getting 1340/512 = 2.62 Mh/J which is in line with what I have measured on my own HD 7970 machines.

It's not exactly nonsense, if he is trying to measure the efficiency of his cards as opposed to the efficiency of his entire system.  Now sure, to be perfectly fair he should remove the idle power usage of the video cards before subtracting the idle from load, but 7970 use very very little power in "long idle", less than 3W per card typically.

Also, he can hypothetically run more video cards on this system without impacting the idle power usage (other than the minor draw of an idle video card).  It's good to know the per-card efficiency to know if it would be worth doing so.

[Dyaheon]

No. It is nonsense to compute the efficiency as 1340/(512-154) = 3.74 Mh/J...
For example, if the cards' idle power consumption would be worse and would be making the machine idle at 350 Watt, would you conclude it would raise efficiency to 1340/(512-350) = 8.27 Mh/J ? Of course not!

You are in fact getting 1340/512 = 2.62 Mh/J which is in line with what I have measured on my own HD 7970 machines.

It's not exactly nonsense, if he is trying to measure the efficiency of his cards as opposed to the efficiency of his entire system.  Now sure, to be perfectly fair he should remove the idle power usage of the video cards before subtracting the idle from load, but 7970 use very very little power in "long idle", less than 3W per card typically.

Also, he can hypothetically run more video cards on this system without impacting the idle power usage (other than the minor draw of an idle video card).  It's good to know the per-card efficiency to know if it would be worth doing so.

Indeed, the card's efficiency is also an interesting number, although a bit difficult to tell from a one measurement of idle/mining. The card's idle consumption may vary depending on how well the idle-features are working. The second card is probably in that negligible "long idle" state, but the primary may be consuming quite a bit if he is for example using two monitors or possibly overclocking with AB unofficial overclocking. At least that's the case for me, my 7970 fails to drop to 0.85V & 300/150 MHz often.

I suppose a better way to find out a card's efficiency in this case would be to compare the power draw when mining with primary card to the power draw when mining with both of them, assuming long idle is working well.

But yes, it's an interesting number, in fact probably more interesting to others than the efficiency of a quite power-hungry system. A dedicated mining rig with low power CPU and such with 4-6 7970s will make the cards' consumption dominant, instead of the system's consumption.

[yochdog]

Alright, I went and re-measured the numbers.  I think what happened was I screwed up the idle wattage the first time around.  Here are the correct numbers:

System idle:  154
Mining with above settings:  512
Hash rate:  1340 MH/s

Soooo, I am getting 3.74 MH/watt.

No. It is nonsense to compute the efficiency as 1340/(512-154) = 3.74 Mh/J...
For example, if the cards' idle power consumption would be worse and would be making the machine idle at 350 Watt, would you conclude it would raise efficiency to 1340/(512-350) = 8.27 Mh/J ? Of course not!

You are in fact getting 1340/512 = 2.62 Mh/J which is in line with what I have measured on my own HD 7970 machines.

All I am trying to measure is the additional power consumption of the cards.  This is a machine that is always on, and has been always on for the last 3 years.  Thus, the idle power consumption is the baseline, as it would be consuming that regardless.  Determining the incremental energy consumption is all I am concerned about, and now have a good approximation of that number.

Now if I was building a dedicated mining rig from the ground up, of course the over-all system wattage would be the important number.  But in this case I am not dealing with a dedicated miner, thus it is not nonsense.

[exahash]

Another big factor people seem to ignore is how much power is drawn once the system has been mining for a while.   I get the sense most fire up their miner, wait maybe a minute, then check the kill a watt.  You really need to let the miner go for an hour or more to see the full effect.

My rigs use almost 10% more juice after getting up to temp (running stable for days) vs the first several minutes or even first hour of mining.

I also watch the amps more than the watts, since I don't want breakers tripping on unattended miners.   Our voltage tends to sag to below 110 during the day from a high of 118-120 each night.