[Antminer S1 Sales open] Price changes daily, now 0.414 BTC for 180GH/s

So does anyone have some information to share about underclocking?

I had a scary moment today when my main circuit breaker tripped. I'm running a large number of miners including 3 S1's. I underclocked everything I could to prevent it from happening again.

I changed my S1's from 375 to 325. I dropped from 190GHs to 166GHs which is fine by me. This isn't about the extra pennies I'm losing by not overclocking. This is about power efficiency and waste heat generation.

Does anyone have stats comparing watt usage for 375 to 325? Is there even more significant efficiency to gain by going lower?

I run mine underclocked (for efficiency due to electricity costs). I get 150GH/S per ~200w @ 300, rather than 180GH/S for 380w. I essentially went through the same process described in the link pvnamk19 posted above.

So you had to do the pencil mod to get to 200w? I'm not really interested in going to those lengths to undervolt. I'm only wanting to underclock. Sorry, I didn't read the entire thread so maybe my scenario was addressed there.

no pencil mod means 2 watts per hash. so a 350 clock gets about 180 gh and around 360 watts with a plat psu

a 300 clock gets about 150 gh and around 300 watts

a 275 clock gets about 140 gh and around 280 watts

but read below:

please get a fucking pencil lightly stroke each of the 8 resistors 2 times do not measure the ohms takes 2 minutes.

set the clock at 300 and see what the results are. about 150 gh and 200 watts is pretty much what happened for me, it is easy to do this.
below one at stock volts and 393 freq gets me 200gh and 406 watts

and one at undervolts 275 freq gets me 140gh and 201 watts

I am thinking about undervolting, got myself the HB pencil, but the resistor that you supposed to touch is so tiny and there is another object nearby (C10). How you were even able to do it reliably? magnifying glass workstation? i think that you supposed to use the multimeter (ohm meter) as well.

I have 3 running on an evga 1300 supernova psu about 420 gh pulling 563 watts at the k-a-watt plug that is 1.34 watts a hash.

I can't tell you how easy it is. I have had cataract eye surgery in each eye and I can do it in 5 minutes

I used a number 6 pencil on one mod and a number 2 pencil on the second mod.

I deliberatively was sloppy on getting perfect ohm measurements after the mods.

I have an hi-end meter all resistors read 4.46 or 4.47 k ohm before the mods.

I allowed the resistors to range between 2.4 k ohm and 3.3 k ohm after the mod .

The key is your ssh. you may want :

250 freq
275 freq
300 freq

if you fucked the resistors up a lot you get x's on your asic's just go to a lower freq.

I stroked the resistors in 1 direction away from the one next to it and towards the empty space. I used a magnify glass on a stand

http://www.amazon.com/Carson-DeskBrite-Illuminated-Magnifier-LM-20/dp/B003EW1ZNC/ref=sr_1_4?ie=UTF8&qid=1401213622&sr=8-4&keywords=magnifying+glass+stand

the photo below is with the glass.

Excellent work, Phillip!