Antminer S5 - Underclock - Undervolt

I'm using two of those little fellas.

There are some 40A/400-500W buck converters in the shop -> that should be enough for VirosaGITS. I wouldnt connect 2 in parallel to one board, because that would be like 2 different PSUs to one hashingboard.

And yes, its a V1.91. I will do some more tests later.

I have little electrical knowledge, so i do not know how to pair up buck converters together to raise the watt limit and keep the efficiency up to 98%. Basically it would be a god send, even if the end cost is 40$ per to keep it running at full speed but with much better efficiency. At least for some users and maybe me if i can get a bunch of the step down for cheap.

Maybe someone with more knowledge could answer as to whether you can pair up a buck converter to raise the watt limit/keep efficiency up?

Also maybe someone can tell us where the S5 hide the image, or the freq list.

New to this thread and TL:DR on the rest of it. GITS referred me here and told me to bring some data since I just picked up an S5 and am doing a project for the school with probably two of these things.
All power measurements are made using a Kill-A-Watt meter behind an HP DPS-800GBA power supply, for some odd reason putting out a loaded 12.65V (12.7V unloaded). Hash measurements are from the management screen on the unit's web interface "GH/S(avg)" box after roughly 10 minutes. Temperatures are in a room where ambient temp was high, around 28C, using the stock (incredibly noisy) fan.

Balls, won't let me actually embed the damn thing...

Quote from: 1slickvdc on September 26, 2015, 02:47:38 AM

Ouch that is bad efficiency. But most of that is because of the PSU itself so it's hard to say how much of it is due to the voltage. Its interesting still. What PCB version do you have? Its written in top right of the PCB under the bitmain logo.

Anyways basically the interesting point is 400-425, youre able to clock it just a bit higher and stay stable with your over voltage. But you get very bad efficient across the board. The highest i could get was 1315, and then it crash rapidly, while you crash a bit later at high volt. I guess it make sense.

Ultimately you normally would draw 580w at 350 and you're at 700, ouch. Also your efficiency go up and down mine didn't it was a bit better in the account of the the fan draw being the same and actual efficiency being the same.

That's why I really want to get the voltage down on that damn supply. The 600W version of that supply has a trim pot and people have dropped it to about 11.6V. My controller board says V1.3 (assuming that's the string that reads something S5 blah FPGA something. The only version number I could find anywhere. On the control board next to where the one hash board connector and the control board power connectors are. The PSU also reads about 35W unloaded.

Can the voltage be modified like my U3's, through editing the config? Saw this in the "monitor" section.

/usr/bin/cgminer --bitmain-dev /dev/bitmain-asic --bitmain-options 115200:32:8:7:200:0782:0725 --bitmain-checkn2diff --bitmain-hwerror --version-file /usr/bin/compile_time --queue 8192 --api-listen --default-config /config/cgminer.conf

one of those "--bitmain-options" params has to be voltage, probably 0782 or 0725.

Quote from: 1slickvdc on September 26, 2015, 03:14:42 AM

You can set the option but the hardware doesn't use it. Since it has some string design or some such it doesn't have voltage control.

You can see the board version here on the PCB not the controller;
http://i1079.photobucket.com/albums/w501/bond007taz/20150129_071133_zpsce3ee8cd.jpg

S5_SPOWER_HashBoard_V1.3 is what it read but its quite possible you have a very early batch S5.

Hash board V1.3 also.

From a low-level sense, there's no reason the chip voltage absolutely couldn't be controlled from the software except by intentional design. Most likely to prevent twits from cranking it up and blowing out their miners. What about a hardware modification? It's a switching supply of sorts to step it down to chip voltage, there's got to be a voltage reference point somewhere that can be modified, eh?

Quote from: 1slickvdc on September 26, 2015, 03:49:40 AM

I really don't know the details. Apparently its because they switched to a "string design", the voltage must be controlled at the feed/PSU level. But again only the 1.91v seem to support it without dropping chips.

Maybe RichBC can elaborate on that, but i'm not the guy for that.

Wait. "string" as in they put the chips in series on the rail?

some not so good news on s-7 underclocking. using this psu

https://www.trcelectronics.com/ecomm/pdf/hrp600.pdf

okay I set freq to 300 which is half speed and I did 2400gh at 612 watts which is normal volts were at 12.15

I dropped volts to 11.85 2400 gh held watts went just under 600 to 594

I dropped volts to 11.50 2400gh held watts went down to 579

At 11.25 volts asics dropped off

so there is some type of governor/regulator on the early s-7 just like the early s-5.

and to be sure the controller was out of the power line it was run with a different psu steady at 12.15

Excerpt from the S5 manual:
"Notes: Input voltage should not be less than 12.00V, since it is based on serial power solution and there is no DC/DC inside the miner. Higher input voltage will cause higher mining efficiency."

What the balls? The only possible thought on why they would do that is an attempt to keep heat down. Other than that it sounds like a terrible idea in terms of reliability.

Quote from: 1slickvdc on September 26, 2015, 04:56:19 AM

And they also had:

"When better power efficiency is needed in the future due to higher network difficulties, you may want to buy some special PSUs 9V DC with more than 10A output, which will allow you to have a 0.2J/GH mining efficiency, but at lower hashing speed."

So err. Yeah, don't ask.

I'm thinking of getting this thing: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_374011_-1 since it will allow me to adjust voltage level and isn't too expensive nor inefficient. Also, I ran the numbers on my power supply based on the nominal consumption out of the manual at stock speeds. My PSU is running about 77%. Ouch.

Quote from: 1slickvdc on September 26, 2015, 05:27:40 AM

How do you find out if you can adjust the voltage? This thing says "Primary Output Voltage (VDC) 12v".

If you really want to fiddle, go ahead, you might want to have a look at which PSU the other user went with for doing this. I think he needed to get 2 5V~ PSU to do 10V~ to keep efficiency and stuff. Hmm.

But it would be a shame if like other user you try to go to 11.5v and then bam it drops and you can't get any effective downvolting from it. I guess in the worse case this could be the unefficient unit and if you make sure the other unit is v1.91 then you'll have the PSU to undervolt it.

http://www.jameco.com/Jameco/Products/ProdDS/374011.pdf find the column SE-600-12 and go down to "Voltage Adj Range" row. There's a range.

Quote from: 1slickvdc on September 26, 2015, 05:32:53 AM

http://www.jameco.com/Jameco/Products/ProdDS/374011.pdf find the column SE-600-12 and go down to "Voltage Adj Range" row. There's a range.

I see, gotcha. A problem someone encountered was that when he went to the lowest range, the PSU went from supporting something like 500W to 100W because the amperage limit also went down with the Volt.

It doesn't seem to say what it will support while at 10V.

Had that problem on this specific PSU?

Quote from: 1slickvdc on September 26, 2015, 05:38:04 AM

Had that problem on this specific PSU?

Turn out the problem with that one was the price. Its being discussed in page 4 and 5. RichBC eventually went with 2x 5v~ to get a range of 9v-11v. Since the one you are interested in work well, but down to 10V.

So its pretty good, if you get it cheap. Others were discussing prices per unit at 230$ and 125$. The link you have is quite cheaper. So look like a good PSU.

Worst case scenario and it's got problem at lower voltages, I end up with a nice high current supply for testing car audio gear I repair. Have to definitely consider this unit.

Quote from: 1slickvdc on September 26, 2015, 05:48:36 AM

Worst case scenario and it's got problem at lower voltages, I end up with a nice high current supply for testing car audio gear I repair. Have to definitely consider this unit.

Well as reported you might be able to go down to 11.5v. Unless something weird happens and you get results that we've only been able to repeat on v1.91. But if not, its not like it can't be used as a "Normal PSU" as well, since it work just fine at 12v. The efficiency isint too bad so, why not.