Topic: [GUIDE] Undervolt antminer s1 [1.19W/GH at the wall] - page 4. (Read 69365 times)

8k75 in parallel with the existing resistor.

OK tell me than what resistor did you use?

Your switch shouldn't be drawing 200W, and unless that 90 is in C that shouldn't be a problem either. Even pre-modding my S1s had no issue staying in spec even in ~50C ambient.

he just said his splitters work fine... and they should. 6pin->6pin splitters are totally fine to use.

please note that these 18awg ebay splitters are often mediocre quality - 100W per split shouldnt be an issue, but if you tried it on a un-modded S1 or S3 you would likely melt the wires and start a fire at >150w per side of the splitter, or the combined >250W on the primary PCIe cable

Undervolted my s1 cheers for the guide

Not sure I do run this one infront of the hole setup so Switch, Outlet , PSU, Antminer all are measured otherwise you don't get a clear picture. One thing most people forget it the Cooling of the room. I am in NEW MEXICO so Desert and have my setup in the Garage. WHich itself is heated up to almost 90 degree with the Antminers now which is nice and warm :-)

Those splitters you ordered from ebay, it is not going to work. You needs to buy splitter with 8 PCI-E that split into 2x6 pins. I tried that in the past, it didn't powered the s1

Another success 140Gh/s @ 170W (crappy thermaltake TR2 450W psu)

Bonus: its wifi enabled so i have a movable hash heater

sad note: to bring her back online i had to take offline my first bitfury M-Board rig who was a pet project (hand building hash cards to expand it from 3) but had become finicky as of late (vibration from slamming doors sent the cards a-wobbling and errors etc etc).

I'm running the majority of them on Emerson DS450 server PSUs, and have a couple plugged into a cheap 850W HEC power supply I got for $40.
http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=7621664
I got the first one mid January, so I guess I ran them almost 9 months before I modded them at the start of September.

Don't get me wrong, I'm not trying to be antagonistic here. The reason I asked about the power supplies was that using the kind of super cheap PSU of the kind that comes free in a $30 case is about the only reason I could see getting 2.75J/GH at stock settings. Pretty much everyone with a decent PSU is measuring closer to 2J/GH.

I would double check your measurement equipment, I have a feeling something is malfunctioning or hooked up incorrectly. Your setup is likely drawing much less power than you're reporting here.

Here are the stats from today :







I hope that helps.

Do you mean something else? Because S1s haven't been around for even a year.

I do use a HP DPS-800GB which gives me a nice 69AMP Rail. I not sure if I would even mess with an 80+ Gold Power Supply those aren't build for 24/7 operations and will sooner or later fail on you. If I would remove my network Switch and maybe the low quality fan's which the Antminer has I might be able to reduce the costs a bit but I am already very happy with what I archived with those old S1's before I upgrade to some high end gear.

How many month do your S1's did ran before you downgraded them ? Mine ran almost 2+ years straight 24/7.

What kind of power supplies are you using for those? Your numbers are quite bad on both ends; with an 80+ Gold supply on 120V I got 400W per unit at 200GH/s, and am now getting 170W at 140GH/s.

Hi Guys,

I am working on this underclocking as well and I got some different results when you use USA Power 120V. First I also tried the pencel mod but wasn't 100% happy with it so I did some researching on my own and found out if you really replace those resistors :

R3, R66, R38, R52

The original capacity of the resistor is: 8.2 - 8.3 K Ohm

I replaced them with an 0603 resistor with 4.12 K Ohm

This got my Antminer's so far down that 3 of those now only do use ~612 Watt. This allowed me now to reduce the GHs/Watt costs  to be :

Original 1650 Watt for ~ 600 GHS = 2.75 Watt/GHS

With the new Setup I get :

Tuned 620 Watt for ~ 400 GHS = 1.55 Watt/GHS

So if you do your math now you do recude your Power consumption by over 43% without buying new Hardware. All you do need to buy is a few 0603 4.12K Ohm resistors which cost like 3$ for 100 on eBay maybe even less.

If you decide to do this with a normal solder iron use a thin pair of tweezers so you can hold the resistor better when you remove the old one. I did start with the left side first which is closer to the next resistor on the left. Since they are SMD you can apply some heat to is and it also soften the other end of the resistor so much that you can lift one end of the Circuit Board. Then you do the other side and you have your resistor removed.
Next apply some solder to the left spot on the Circuit board and with help of your tweezers solder the new one in place as flat and good as possible. Than do the other end and measure with the Ohm Voltmeter and you should get between 2.8 - 2.9 K Ohm. Ensure you soldered it in place so it don't come loose.

!!! WARNING !!!!

When I did one of the 6 boards  I did mistakenly not solder one resistor perfectly flat onto the ciruit board and when I put Power onto it it burned me 4 of the 8 Chips. When I did remeasure I noticed I suddenly had the wrong OHM which caused an over voltage to the chip. So please measure twice.

Once done SSH into your Antminer to ensure it benefits from it's now lower Voltage by adjusting the multiplexing for chips :

        option 'freq_value'    '0A81'  #275M
        option 'chip_freq'     '275'
        option 'timeout'       '45'


This is the best Value you can archive now. Going higher or lower will reduce your GHS power.

Some other help for this modding (Freg|Timeout|HEX) :

 250.00  56 0981, 1385, 4981, 5382, 5385, 6786
 256.25  54 1405, 5405
 262.50  53 0a01, 1485, 4a01, 5485
 268.75  52 1505, 5505
 275.00  50 0a81, 1585, 4a81, 5585
 281.25  49 1605, 5605
 287.50  48 0b01, 1685, 4b01, 5685
 293.75  47 1705, 5705
 300.00  46 0580, 0b81, 0b84, 1785, 4b81, 5785
 306.25  45 5805
 312.50  44 0c04, 4c01, 5885
 318.75  43 5905
 325.00  43 0600, 0c84, 4c81, 5985
 331.25  42 5a05
 337.50  41 0d04, 4d01, 5a85
 343.75  40 5b05
 350.00  40 0680, 0d84, 4d81, 5b85

~~~~~~~~~~~~

Also a big thing I noticed is if you lift the little Controller board and tape the top between the 2 Boards with Tape you get a much much better Airflow as you can see on the photo below :





This board is modded with new 4.12 K Ohm resistors.



~~~~~~~~~~~~

Lumanet Solar Energy LLC ( http://www.lumanetsolarenergy.com )

We do also offer soon remoded hashboards for sale over our Portal. Also we work on a 800Watt Server Power Supply Combo which will be below $80 but has a 69Amp 12V Rail. Which can be used to feed up to 4 underclocked Antminer S1 or 2 Antminer S3
 
~~~~~~~~~~~~

I modded first some miners with 3.3k resistors and they work at 250mhz about 120gh/s.

Then I bought blue box shaped 10k multiturn trimmers which are much easier to solder in place. I solder the legs direct to pads where the original resistors were, little bit hot glue secure them in place.
2.9 to 3k total resistance and 300mhz 150 gh/s with miner that worked 393mhz with 0% HW.

Other miner with same trimmer mod makes too much errors what are the hex value for 297mhz and timeout?


WHY Bittmain advertices using silver thermal paste which is usually conductive with S1 uppgrade kit if it leaks like original short circuits will follow

No, it makes no sense to me. Guess I'm dim witted.

I know exactly how much torque it takes to power up my car to a speed of 100 miles. Do you?

When lowering the resistance on the 8 resistors make sure you're not also lowering the resistance of the 60k ohm directly above it. I have all of my eight S1s running at about a 1.17 J/GH effeciency.

Note that we should really be saying J/GH since a Joule is a unit of energy where W (watt) is the power or rate of energy use (watt=J/s). Also to compare apples to apples, or rates to rates, W/GH should really be W per GH/s to measure two rates (power, or rate of energy use, and hashing rate). Then the seconds cancel out if you W with J/s and get the proper J/GH, which is how Bitmain rates efficiency. As an electrical engineer it bothers me seeing that. It's like somebody asking how many horsepower does it take you to go 100 miles

just a quick note. 0.75v is not enough. Even 0.8v is not enough...

I find the minimum acceptable if you want low HWE% is 2.9kohm, but to be safe, a minimum of 3kohm is best...