ANTMINER S5: 1155GH(+OverClock Potential), In Stock $0.319/GH & 0.51W/GH

[sEpuLchEr]

Damn it. I really want to buy but but but but... too many buts.

Someone please help convience me.

[ZiG]

Damn it. I really want to buy but but but but... too many buts.

Someone please help convience me.

Just don't buy ...let the other people - like me -  experiment for now ... 

It's my Christmas' gift ...

ZiG

[sEpuLchEr]

Just don't buy ...let the other people - like me -  experiment for now ... 

It's my Christmas' gift ...

ZiG

Well, even if it run perfectly well for you, unless you're situated in Singapore where the season are hot, hotter and hottest, there is definitely more chance of a chip failure for where I am. Unless I host them at a NOC but I like to feel and touch my miners. I've got a fetish. 

[infernoman]

just wondering if the different options will now ship directly into canada. i'm looking for the option that includes the duty fees into the cost of the miners. so i dont get hit with any unexpected costs.

[Minnesooooota]

BITMAIN, how often do you update the bitcoin/usd price on your site? current price is 334-335, and your ticker is stuck at 328. for a large order, that makes a hefty difference. i placed an order, and i didn't realize your bitcoin price ticker was not being updated... 

[Rabinovitch]

Just pay via bank transfer. 

A little promotion of S5:  https://forum.btcsec.com/index.php?/topic/10755-antminer-s5-ot-bitmain/

 

[buysolar]

will there be an upgrade kit for the s1's and s2's??

I hope so. I'd like a bunch of upgrade kits for my S1's

[klondike_bar]

Another thing that really worries me is the chained design. Does it mean if one chip fails, the whole board fails?

So instead of getting 00XX0X00 we get -----------------?

Please tell me I'm wrong.

Hi, there will be two kinds of possible fails. Both are possible.

But string design makes the PCB very simple, which left far more less possible reasons for the hardware to go wrong. That is what we have seen in the S3++, a private batch which use chained design with BM1382 chip.

Thank you for your reply. But like you said, there is still a chance of failure. With the current S4 for example. Even if one chip is completely dead. I can still use it. But with the chained design if one chip goes silent, that's it. End of story.

I like the power efficiency but your price tag.. and the chance of having one miner out of action just because of 1 single chip... I don't know, it's nagging me in my head...

If one chip fails it shouldn't affect the rest. The chip schematic has multiple Vin and Vout pins, and the only way to knock out the entire chain would be disrupting the voltage drop across chips. The s1 and the s3 both used chains for the data already, chaining power is the only new thing.

[raskul]

However, SP20 is a known performer, while quality of S5 is unknown, but I expect it to be good.

What makes you expect that?..

it's just probability...S1 was good, S3 was good (for me); S5 seems to be more like S1.
S2 was not great, but not bad. S4-did not buy because of power supply problem in batch 1.
The caution for me is in the chains while in SP20 you can regulate chips voltage-very neat.
I got one, will buy more SP20, S5 or both-will decide soon.

s5 is a much riskier design due to the chain.. if one chip dies, the whole board goes down.
I've opted not to order now that I realise they have chained the chips.

[raskul]

Interesting product. A lot will depend on pricing, but at similar pricing and efficiency I think you'd have to give the nod to the SP20 due to many of the reasons other people have listed here (established product, ease of changing settings), but also due to the potential risks inherent in the chained design. Bitmain saves significantly on costs by eliminating the VRMs and should get a small efficiency boost from it as well, but so did AM and everyone saw how the Prismas turned out. This wouldn't be a product I'd be investing a lot of money into until the first batch is field tested for awhile.

Thanks for your opinion. We have done a small batch of S3++ in the domestic market, which employee the string power design on the BM1382 chip. It works stable and sound until now.

it's not the same ASIC, the community haven't tested the string design and I, for one just cannot take anything that dogie will offer us when he reviews, on the simple fact that you are paying him to do so. I have serious reservations about this miner.

[raskul]

Another thing that really worries me is the chained design. Does it mean if one chip fails, the whole board fails?

So instead of getting 00XX0X00 we get -----------------?

Please tell me I'm wrong.

Hi, there will be two kinds of possible fails. Both are possible.

But string design makes the PCB very simple, which left far more less possible reasons for the hardware to go wrong. That is what we have seen in the S3++, a private batch which use chained design with BM1382 chip.

the fact that it was a

private batch

and you didn't open up sales, is a big red flag for me. You must have had problems that you wanted to hide?
why not just open up S3++ sales? I don't understand the logic here. It's not like you to remain so closely guarded.

what went wrong?

[raskul]

-snip-
If one chip fails it shouldn't affect the rest.

shouldn't

but...

does.

*cough* AM's Prisma chain design:

[Melty Melty]

https://i.imgur.com/hAss6mY.jpg

Intron tried a stringed Bitfury design too. The problem is that they like to fail short, and when they do all of the others in the string get a proportionally higher voltage. Cascading failure and the magic smoke comes out, or magic black goop in the case of Bitfury's chips. I think they eventually got this one functioning under a slightly different design, but it makes me nervous all the same.

[sidehack]

This is the fourth string miner that I know of - the others being the OneString and Yazio (or whatever) boards with Bitfury chips, and the Prisma. I know plenty about how reliable the Prismas are, but not enough about the Bitfury-based boards. (A previous post mentions a fifth design I had not previously seen, so chalk that one up).

klondike_bar's assessment is not entirely correct; the active players in the circuit are voltage and also current. The capacitors at each string node will help balance out brief changes in current (which are natural occurrences with all the switching going on in the chips) to help maintain a constant node voltage, but won't really help much if one of the chips drops out entirely. Suddenly the current path at one node is cut in half, which means that, unless external provisions are made to compensate, the second chip in the node will have to push twice as much current as otherwise expected. This might result in the voltage across that node increasing until the chip is allowing that much current through, which will greatly increase the power dissipation (potentially quadrupling it) on that chip which very well might roast it. The best case would be the chip fails short, in which case you now have an unbroken current path, but with one of 15 nodes out, the rest of your chips' voltages increase by about 7%. If the chip fails open, you now have no current path and the entire board is down.
If, on the other hand, instead of the node voltage increasing until the current draw is in accordance with the rest of the two-chip banks, the current stays low and starves out the other banks, now you have a board which technically works but does not operate stably.
If each bank is provided with an active dummy impedance working alongside the capacitor, the two systems can effectively buffer the node voltages and chain currents to keep every chip functional. If one node's voltage starts to increase beyond what capacitor ripple can handle, this indicates it's not passing full system current and the dummy impedance can open up a bit to allow excess current through, keeping the system operating and the local node voltage at the expected value. If there's a stably controlled system like this in place, I'd have a lot fewer qualms about running one of these boards (we're actually toying with designing one of our own using that principle). I don't really trust unregulated strings as they are, but if there's some node-level regulation at least, it's certainly got more potential for stability and reliability than just trusting the chips to all operate within a narrow tolerance of "identically".

Another thing that's probably not something anyone wants to do, but could greatly assist the reliability of a chained design, is individually fused chips (alongside a controlled dummy impedance). If one fails short and overcurrents, the fuse blows and now that portion of the bank is an open circuit. Your dummy impedance will have to take its full share of the current, so with a chip like BM's where it's expected to draw around 9W you'll need a well-sinked dummy but that's not difficult. If an entire bank goes out, the dummy impedance will have to take the entire load, but it avoids the problem of overvolting the rest of the chain.

[Melty Melty]

I don't really trust unregulated strings as they are, but if there's some node-level regulation at least, it's certainly got more potential for stability and reliability than just trusting the chips to all operate within a narrow tolerance of "identically".

There's a post somewhere in the depths of the forums where someone got the Bitfury chips working straight from mains voltage in one huge string. I don't know how long it lasted, but I don't imagine it would have been particularly stable with the Bitfury's internal oscillator and the wildly swinging supply voltage. Absolutely lethal device with rectified mains voltages exposed everywhere, but impressive none the less.

[sidehack]

Dang. I really hope he used an isolation transformer. That's a buttload of chips too.

Novak and I were chuckling earlier today, wondering how long it would take for someone to ground-isolate and stack three server PSUs, and stack four S5 in series to get 9V per machine. The only problem there will be ground loops on the ethernet cables causing your switches to explode, but it could be interesting nonetheless.

[Melty Melty]

Novak and I were chuckling earlier today, wondering how long it would take for someone to ground-isolate and stack three server PSUs, and stack four S5 in series to get 9V per machine.

Took me an embarrassingly long time to work out where 9v is coming from. There's one chain per blade, two chips per voltage step in parallel for a total of 28, so each gets potential of 0.64v. I'd actually already begun thinking of how to do something insane like that, except I was going to replace the BeagleBong in each with some optoisolators on the SPI chains. Wouldn't be a massive undertaking to get 0.24W/GH out of the things but I don't know how much you'd be saving over the normal DC-DC, or more importantly if it would be worth it or not.

Love to get my hands on their chips and make a higher voltage blade, though I'm very inclined to think that they've bought Bitfury 3 masks.

[raskul]

I didn't want to clog up this thread with these speculations, so i made a new

https://bitcointalk.org/index.php?topic=903102.msg9922620#msg9922620

[sidehack]

I sat down one morning last week and worked up a rough design for relatively-low-bandwidth (maybe good for 1MHz, which should work for any practical miner's UART or SPI) logic level shifters and a constant-node-voltage current dump circuit which could, in theory, be used to chain any kind of chip with any arbitrary voltage. It's probably just a loose implementation of ASICMiner's proprietary PMS01 chip, which looks to be a pretty nifty device.
We're also contemplating working up a high-current (and hopefully high-efficient) inline regulator to make undervolting string miners easier off existing 12V PSUs. The basic design coincides with some other projects we're working on anyway. Something like that would be handy to strap some S5 (or Prismas) behind here in a few months.

I don't know if the S5 uses isolated or level-shifted comms, or some daisychain implementation like the Bitfury chips did. Haven't scrutinized the PCB photos enough yet to make an educated guess.

Also, the S5 has 15 steps in the chain (30 chips) so 9V would drop to an even 0.6V per node.

[Melty Melty]

Also, the S5 has 15 steps in the chain (30 chips) so 9V would drop to an even 0.6V per node.

There's 14 steps not 15. 0.64v at 9v.

I don't know if the S5 uses isolated or level-shifted comms, or some daisychain implementation like the Bitfury chips did. Haven't scrutinized the PCB photos enough yet to make an educated guess.

If you look at the photos of the back there's level shifting.