Yeah I don't think I've heard anyone claiming they would run under 10.8V.  You have access to the web interface because it doesn't affect the controller it's probably BM1384 chip I/O of some kind or other.

We have a BM1384 on our breakout board running at 0.625V right now, which would be 9.375V into an S5.  It's not a chip limitation, it's a miner design limitation.

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novak

Efficiency doesn't change much with clock speed because although dropping the clock reduces power consumption, it also reduces hashrate, and both are approximately linear effects.  The way to boost power efficiency is if you could also undervolt- something that apparently does not work well at all on the S5.

The BM1384 chip on the S5 theoretically allows significant undervolt but even apart from the difficulty of finding high efficiency 8-10V power (required as the S5 is a string miner) the S5 has something which evidently just doesn't work if you drop the voltage much.  Sidehack has said he suspects the (chained) clock line, at any rate some of the chained signals and the related I/O voltages are most likely suspect.  As far as I know no one has taken the time to mod an S5 to be able to undervolt or could tell you what is going wrong for certain.

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novak

For 16 pin or 18 pin connector ?

np just wanted to make sure u replied since i have noticed people read a few posts and when they hit one disputing something another poster said or asking if its true they dont continue reading they just take that as being fact and spread wrong info so hopefully others will question y what i mentioned wasnt provided but promised and since its not provided y wasnt some sort of compensation given to those that purchased the miner (in my case at 100+ more then the current price because it was batch #2 directly from bitmain) based on false untested claims that were later found to be lies and were silently changed. it was so silent that up until the 29th of march i had no effin clue about the change. i read that maybe a firmware update will allow better functionality for under volting them down to 9v because as they sit they dont unde rvolt at all reallyand any changes below 12v make the miner act all sketch causing mining issues or the controller wont detect the boards at all so i emailed them asking what the exact model 9v 10a psu was used so i can try it out myself with the same hardware they used to test it but sure enough i soon found out that they didnt actually test their bold ass claims. sure i wont run at 9v right now because .5w per gh/s is fine for many people but when the diff gets higher or electricity costs go up then undervolting was supposed to be there to allow us to run them at a much higher efficiency rating so they can be in service longer then they would be if they couldnt be under volted but all in all i know i cant be the only person that saw those numbers and was thinking exactly what i stated above....no one likes buying new hardware....especially when their current hardware never hit a roi point so even at a slightly higher cost we were suppose to be able to basically hit or get much closer to the roi point if the diff started going up by leaps and bounds like it has in the past now we are stuck with once .5w per gh/s isnt worth it anymore we have to sell these and start all over again with new miners....i wonder y they havent replied to this thread yet.....probably the same reason this threads op didnt reply to my pm when i got my s5 and had problems seeing the "quietness" of the miners.....sad.

   Maybe he has  a way to hook up cables like this.

 The breakout boards are nice but 2 grounding bars are 14 bucks.  what's the break out board cost?

http://www.amazon.com/MURRAY-ECLX075M-Ground-Terminal-Positions/dp/B007ZZGVOW/ref=sr_1_2?ie=UTF8&qid=1427814028&sr=8-2&keywords=ground+bar

Do you have reseller or supplier in Australia?

j4bberwock, do you have any more of these boards in stock?  HolyBitcoin doesn't have them listed as an available product.

Thanks for the info J4bberwock , start looking for the regular PSU rite now , the reason i dont want to order PSU from other my country is the F*C*kin Tax are too high now , The customs just kick me with 35% tax from the original Bitmain price.....damn

Best Regards

wheew , 2-3 weeks delay that something for small miner like me   thanks for the reply J4bberwock

What is the best way to overheat the miner to check if it will shut down at 80C?

Put something infront of the front fan?

I've got 3 new 220v 30a lines being installed today.  Might have to look at trying one or three out when you solve the fan noise issue.

I'd have to check my notes, but I don't believe it would start at 10V. I had to start it at a higher voltage and then turn it down as it was running.
If I had to guess it's a limitation of the string design as opposed to the chip itself. The numbers Bitmain gave are likely accurate for those voltages, the S5 just won't get there. Hence why they removed the language in their thread that it could be run at 9V.