I run a farm of about 100 S9s currently.  I'm looking to do a purchase of a dozen or so more miners and am really torn on what to do.

Price/TH wise, especially with the coupons Bitmain has been providing, the S9 is still the winner.

However... the Avalon 841 has a lower power consumption/TH, worth about $100/year/miner to me in electrical savings/miner.  But they are more expensive, even with 2 years of running factored in.

However... adding more S9s now to add to the S9s I have been accumulating since June of 16 (yeah, I have a few Batch 1 S9s...)... well... they are feeling a bit old, architecturally.  Top that off with paying anywhere between $1296/S9 last April to $2725/S9 last December, and remembering them for around $1145 back in October, I have to believe that Bitmain will substantially drop their prices when they come out with their anticipated 14nm S11.  That would, of course, reduce the resale price for whatever I bought at todays relatively high $1915 (Even with $450 off coupons they are still more expensive than most in my farm).  Just looks what they did with T9s recently:  dropping from ~$2000 to $1400.

But... if I order S9s soon, I'll probably get about 20 more days of computing time.  At todays price & difficulty, thats about $6/day/miner after power cost.

And...  The next Canaan product, the 861, is close - but its just an 841 with an internal power supply - so no tech change.

Of course, if Bitcoin jumps to $25000 this December, anything bought now will appear to be a brilliant move.  But we are living in an $8500 bitcoin world today.

So.  Speculators:  Is anything coming in the next couple of months that will shatter the current price/performance/consumption curves?

What SHOULD I be worried about, given that I tend to buy about a dozen miners at a time as I fill my data center?  (e.g.  I re-invest as I go, so won't take a loan to buy 60-80 841's directly from China, although I keep thinking about that.)  FWIW:  The advantage of growing incrementally is that even mistakes get moderated out over time.  Of course, no quick riches either.

Your thoughts?

Oh, just to share on speculation:  Most of my Bitmain coupons expire in June.  Therefore I expect a major announcement and price drop on S9s shortly after expiration.

Everything remained well in spec with the Lowes filter in front, but that is of course, VERY dependent on your intake air temps.

He stated he had a spare controller and tried that, but the problem returned...

Samosamo - did you move controller cables with the controller, or did you use the ones with both test?  Did you use the same power supply each time?

I've also found that adjusting the torque on the fan screws can help some.

If your willing to replace them every few weeks, Lowes sells thin poly heating duct register filters in something like a 12 pack.  Ripped in half, they are just about perfect for sitting over the intake grill and will greatly change the tone of your fans.  I only used them on my high pitched whistlers , since I found that noise the most annoying.  You will get a few degree bump in operating temp if you use them - but that generally beats a headache from the sound.

Also... be very specific:  That is 7 amps at 220V, not 110.

Depends how handy you are and how comfortable you are building your own electrical stuff.

30 amp power using 10 gauge (Orange in the USA, not sure internationally) wire.  I would go to home depot, buy the male counterpart, some wire, electrical boxes, and sockets and wire myself up a custom made extension cord.

Note that unless you have a 220V power cord for the supernova, you will likely have to cheat and use a 110V sockets wired at 220V, so your power supply cord will fit.   That is NOT code.

It means you have a bad board.  ONLY thing to try is either downgrading to the 0417 firmware or if there, upgrading to the 1117 firmware (April vs. November) and that is a long shot.

Otherwise, if your miner is under Warranty, contact Bitmain.  If not, see if MyRig is still accepting board repairs or contact one of the repair people here and see if they have time to look at it.

100A is typically a sub-panel.  I have older rental homes that only have 100A for the entire house...  100A circuits, even at 220V, would have HUGE wires coming out of them that would not fit into any typical outlet.

Check for branch breakers on that panel.  They are likely below the 100A one.

Amperage is, of course, based on voltage.  Amps = Watts / Voltage for single phase power.  A good ballpark numbers for an S9 is 7amps at 220V.  Most any power cord designed for a computer should be able to handle that.  Different story if your running at 110V, but that is not recommended for a number of reasons.

Agreed with BitMaxz - if its not broke, don't fix it.

That said, if you ARE having problems, like the miner not reporting chip temps, upgrading may help.  Likewise if a miner is not seeing cards or otherwise acting flaky, downgrading/upgrading might help.  Plenty of reports of DOA boxes working fine after being downgraded...

Back to basics...  Oil immersion is a HEAT solution.  Unless you overclock, your not going to affect your direct mining power consumption.  You could affect your overall power consumption if you were to stop using air conditioning and did your heat rejection outside (e.g.  Had you cooling radiators outside) instead of inside - but few spend the money to recirculate and cool the waste heat - most just eject it outside directly.

That said, the #1 enemy of any electronics is heat (with the possible exception of lightening and other power surge issues).  Keep any electronics cool and they will last longer.  Its why old data centers use to run at 60F... back when power was cheap and computers were expensive.

Hi all -

One of my S9s keeps dropping one card.  When I examine it, I see that one pin on the power connector is off-colored compared to everything else.  Often just resetting that connector will get the card up and running... for awhile.

Is there any way to clean that pin?  What would I use?

Heat does not qualify as air pollution... and the S9 does not, in itself, generate any.  The power plant likely does of course, but that is not something you have any control over.

That said, you still need to get rid of the heat, so oil immersion buys you nothing but cost you a fortune to setup.  You won't save anything on space either, since the S9s are pretty compact.

This is fairly routinely asked, suggest viewing this thread:

https://bitcointalk.org/index.php?topic=622998.0

For what its worth, I had a T9 recently fail.  Shipped it to California for about $30 via USPS, and received a new one directly from China about 3 weeks later (was notified within 2, but it takes a week or so to get here).

Either lower the frequency and hope the chips can handle it, live with it, or declare your S7 as dying.  Typically knocking the frequency back a bit helps in this situation.

Of course, we are presuming adequate power and good cooling.

That would be a specific configuration issue for whatever mining software you are talking about.  Likely its just different pools.  It it VERY common to have a primary pool defined and one or two backup pools defined.  Doing so protects you when the primary pool goes down (not that the major ones do very often), and allows you to continue to mine on one of the backups.  When the primary comes back up, most mining software will switch you back to that primary.

ps.  Ignore the scammer that replied, he/she/it will likely be banned soon.

Or Google "Raspberry Pi power supply" and take your pick.

One wallet, with one receiving address, is all you need per coin you wish to mine.  Multiple addresses just make your housekeeping easier - like being able to keep track of what you make from different pools:  just set up a different address for each pool.

Many of the older mining software, like cgminer, had a "balance" option that would allow you do split hash between pools.  It never worked particularly well.