Topic: How i can undrervolt Ant minter s1 ???????????? (Read 3364 times)

So to be sure then, it looks like I can underclock three S1's at 300mhz and get around 155gh/s each and be fine on say a 850/900w psu?

Stock for 1.0V is 2.5GHs/chip @ ~313mhz, so you're only OCing by 4%. 325mhz @ 1v should = 188W from the chips. After VRMs, draw goes up to 235. Plus 30W for controller and fan, and draw goes up to 265. On a 90% PSU, draw is 295W from the wall.

325mhz = 166.4GH/s. This gets you 1.77W/GHs from the wall.

*note* Just an estimate. May be higher due to higher voltages on chips closer to the VRMs, or lower due to the VRMs running more efficiently. Fan speed might also save power. Point is there are a lot of variables, so idk.

420GH/s @ 500W even. That's lower than what I was expecting. I like!

140.8GH/s @ 275mhz means each chip is doing ~2.20GHs/chip. They say 0.85W should be making 2.0GHs/chip, which is a stock of 250mhz. You're OCing 25mhz (10%) above the spec for that voltage. 1.993A per chip x 64 chips, plus a 10% OC means the chips are pulling 119W @ 0.85V. I understand the voltage is slightly higher on the higher chips, so they'll pull more (more W, same A), but I'm averaging.

That PSU is 80PlusPlatinum, which means 92% efficient at 50% load. That means each Ant is pulling ~153W from the PSU. Add ~10W for the controller, and another 5W for the fan (cuz it'll be on low), and you're only looking at 14% inefficiencies from the VRMs.

Our OC ants pull 201GH/s @ 393mhz @ 1.11V. From the wall is 405W, on a 90% PSU = 365W from the PSU. 3.359A per chip (x((393/350)x1.11))=268W (from the chips). Add 10W for the controller, 20W for the fans (I'm guessing here). That means that the VRMs are 20% inefficient on our units.

If we were to go down to 0.75V, and do a 10% OC, you're looking at 112.6GH/s. You're looking at 75W chip draw. Add 14% VRM inefficiencies (although it could be lower than that), and you're looking at 87W draw from the boards. Add 10W for the controller, and 3W for a low power replacement fan, and you're looking at 100W even (from the PSU). Add a 92% PSU, and you're looking at a 109W draw from the wall. This gets you 0.96W/GHs from the wall.

Very awesome dude!
I wonder what 1v @ 325mhz will yield, it should be doable, I got a U1 @ that setup and its 0% HW

In this case, under heat you will get a lower reference voltage at the voltage divider. So your HW errors would likely go up if you maintained the same frequency.

This has the opposite effect of pencil modding to increase voltage, where you'd be putting lead on the other resistor.

I made a quick guide https://bitcointalksearch.org/topic/guide-undervolt-antminer-s1-119wgh-at-the-wall-526060

Since its a pencil mod, just make sure the voltage remains the same, as pencil makes different resistance under heat.

Maybe with lower resistance give lower hw?




.

The HW has increase (before I had 0.1 ~ 0.2%).

I used pencil mod on R3 (4.47kOhms => ~2.9kOhms)

Awesome!

What resistors did you use?

Also, compared to standard and overclocked how is the hw percentage rate changed? Better or worse? Or same?




.

I have succefully undervolt 3 antminer s1

the result are fucking awsome :

chip are at ~ 0.85 volt, freq is 08A1 (275 MHz)

~ 140 GH/s per antminer s1

500 watts at the wall for the 3 underclocked ant ! (166 per ant for 140 ghs)

The PSU is a corsair AX1200i

for comparison at stock volatage it's was drawing 1050 WATTS for 3x180 GHS !

I will make a topic to explain how later (I need time to see if it's working well)

It's running for 1 hour now without problem

the first ant  has 0.95 % of HW
the second ant has 0.3 % of HW
and the last has 0.5% of HW

Right.

I am also anxious to see some results.  This could be a game changer for profitability calculations by extending the life of our miners.  Once the revenue dips below energy cost, we can swap our resistors to improve the efficiency (at a reduced hash rate) and get many more months out of them.

Anyone managed to change resistors. We need results.

how do you get the voltage of the asic with multimeter (on the board) ?

Hmmm. I was just going off the schematic, but it's possible they updated it. The same principle applies though.

I tested our Ant, and R12 and R3 were both 4.45k?! This seems to be different than what you measured, and means to drop the voltage down to 0.78v, I gotta replace the 4.45k with a 3.07k resistor.

pencil mods work well long-term, but be aware that they 'bake-in' and with age and heat the resistance lowers slightly from when first applied.  In the case of pencil-modding bitfury cards I often had a card run fine for 6-24 hours after a pencil mod before getting to a point that it couldnt stay stable for more than an hour at a time. Keep that in mind and leave a bit of headroom when testing a pencil mod.

Now that the right resistance/voltage is functioning on the bitfury, I am getting about 36-39GH per card

Pencil mods are great for testing, or for minor bumps. According to my math, I would have to swap the 8.2k R3 with a 5.6k resistor, and that should bring the V down to 0.75? Anyone else want to double-check my back-of-the-napkin math?

This weekend I'd like to grab one of our S1s, underclock down to 200, replace all 8 resistors, and then see what the power difference is. After that, I'd like to see how far I can OC on 0.75v before the hardware errors go >1%.

I don't see why you couldn't try a pencil mod on an S1. They just use a voltage divider to provide feedback of the output, so you'd pencil mod one to increase the voltage and pencil mod the other to lower it.

On the Antminer S1 that's R3 (8.2k) and R12 (9.76k) for the leftmost VRM, under the inductor. To make the voltage go up pencil mod (lower the resistance) of R12, and to lower the voltage pencil mod R3 instead.

bump!