SP20 should be counted as a 1.3-1.4TH miner, not a 1.7 - it's bloody RARE for one to achieve 1.7 unless you have VERY cold air to feed it.

 Outside of that, it IS overall a much better miner than the S5:

 Far more configurable, with built-in undervolting will be profitable at quite a bit higher network diff than the S5 can achieve without the use of rather pricy "special" adjustable power supplies that don't tend to be as efficient as common ATX "80Plus Gold" supplies.
 Can be pushed for somewhat higher hash rate abet at the cost of a bit worse efficiency than an S5.
 Much better temperature monitoring.


 I find the "auto-tune" stuff to be a minus, but some folks prefer it.
 Stick shift vs. automatic I guess.

Doubtfull, but it might be possible in theory.

 There are other hardware solutions for other uses of SHA256 out there, though.

Currently own 5 S5s and a single SP20.

 Cleaned out Amazon a while back, except for an attempted purchace from HolyBitCoin that never went through (the canceled it on THEIR end, and a week later were listing at least one S5 for quite a bit more - but they also never charged my card, so no real foul just irritating).


 I've had too many issues with stuff bought on eBay to trust that site with high-dollar purchaces unless they are local, and their tendancy to FORCE you to use that ripoff Paypal company as a payment method (I was one of the original "class" from the first class action lawsuit against PayPal, and REFUSE to have anything to do with that ripoff of a company again for any reason ever) makes it very difficult at best for me to participate in ANY eBay auction.


 I'm not offended by "value" opinions that vary from mine.
 I probably tend to be pretty far towards the "pessimistic" or "conservative" estimate end of the scale here on future Bitcoin pricing and probable future diff increases.

 I've also been burnt by bad estimates on RoI calculations when I was more optimistic about that sort of thing.

 As it happens, I haven't bought any miners for a while - as I see ZERO chance of anything current achieving RoI before the halfing and pretty much NOTHING current except perhaps the S7 for a short while will be profitable at all after tha halfing, per my current projections.

 If actual pricing is higher than I am willing to pay to achieve a REASONABLE CHANCE OF ROI, that just means most of the market isn't doing projections of RoI based on what I class as reasonable projections, or possibly some folks have a TON better electric rates than I have - or the most likely cause, inertia leading to failure to adjust pricing to what is really fair by current standards.


 There is nothing new about "market pricing" being higher than reasonable. or price adjustments being slow to respond to external changes, or a market going with "optimism for the future" instead of paying attention to current conditions.
 Try watching the Dow Jones over the last 5 years - crazy high levels of stock price increases while the economy as a whole is barely recovering from the Great Recession and most corporations are NOT actually doing all that much better overall.


 Mining right now is lower profit than it pretty much has ever been, BTC pricing has been edging up lately but NOT enough to match recent difficulty increases - and the only reason diff increases haven't been higher for the last month I suspect to be the shipping delays BitMain has been having on the already-sold S7s.



 Your opinion may vary. Do not fold, spindle, or mutilate. etc.

The only real way to know would be to get figures from each manufacturer - and even that might be an issue since some have gone out of business, and some might want to "fudge" the sales figures to make themselves look better.

Given the many issues with the Neptune, though, I'd guess your guess is somewhat on the high side for that unit.
I'd also guess your SP20 number is low, given the price war between those and the S5 that happened for a while.


 I remember seeing the S4+ being listed as using the BM1382.


 Bitfury definitely made and sold a bunch of chips but I doubt if they ever designed a board much less a miner for anyone but their own usage stuff (MBP and close associates might be an exception there given they were working together for at least a while).

Seasonic X1250 (Gold) or their 1200 watt Platinum unit should work.
Many folks like the EVGA 1300 G2 gold unit, though it's a hair less efficient than the X1250.
 The EVGA tends to cost a little less than the Seasonic gold is probably what makes it more popular.


 I tend to be conservative on PS usage, never run them real close to capasity, so my pair of X1250s running one Antminer S5 and half of my SP20 each is definitely overkill. 8-)

 I would not pay more than $300 all-up for a SP20 at this time, and would be hesitant at more than $250.

 Even that would depend on my geting moved VERY soon to a very cheap electric-rate location (which isn't happening as soon as I hoped).

The main problem with solar is that the capitol costs of the panels are still pretty high, making it UNcompetative with many other forms of power generation overall in most areas and fairly expensive even in areas it works well in.

 It also requires a VERY LARGE investment in batteries to deal with the timeframes when the panels don't get enough light to generate usefull output.


 This has changed quite a bit over the years, as solar cells have gotten cheaper and more efficient, but it's still not to the point of being competative in most areas.

 diff increases never stopped, though they DID drop to an average of appx. 1.6% per increment for the first half of this year or so - despite NO new miners showing up in that timeframe.

 I would estimate diff will see average 4-5% for the next 8-10 months as the "currently new gen" miners get widely deployed, then flatten out some for a while, then one last big "months of jumps" when the full-custom 14/16NM generation chips/miners start getting widely deployed, then a very LONG slow climb period after that as no new technology will be available for a while to push efficiencies up a lot.

 There are quite a few places in the world that can match the lowest electric rates in China quite closely, or even beat them.
 One small such area of them happens to be in the USA.
 Others can get very close, with a lower average ambient temperature to make cooling trivial.

 There are many factors involved in why a lot of big mines are in China, electric is NOT the only factor to consider.

You apparently didn't read all of my post.

 I didn't say I have SEEN S5s at $200.

 I said I would not bother buying one for more than $200.


 This is based on what I figure an S5 will be able to generate in profits between now and halfing, when the S5 and all of the same-gen machines (SP20 and Avalon 4.1 specifically included) probably will become unprofitable at almost any electric rate other than free, plus a small allowance for needed power supply (which can be reused, so only allocating a few dollars there) and a desire to actually profit from having the machine at all.

 I do NOT count on "resale value" as that is already dropping with the price pressure from newer and much more efficient machines, and will probably tank VERY hard shortly before the halfing.
This year has been very ATYPICAL for used machine resales due to the very long period of almost flat difficulty increases, it's not something to count on.

 With electric THAT bloody expensive, your probability of achieving RoI on ANY current or recent miner is pretty much zero - in fact, the ONLY currently available miner that would show ANY profit at all would be the S7 (possibly a SP20 if you clock it WAY down for max efficiency or an S5 if you can undervolt it enough - many S5s CAN NOT undervolt at all though), but you'll be spending so much on electric to feed the miner you'd never pay the thing off or even come close.


 NOTHING other than ASIC has a prayer of being profitable for Bitcoin mining - Pi don't use a lot of power but they would hash in the KILOhash/sec range, even slow ASIC are multi-digit GIGAhash/sec and current ones are pushing into the multi-TERRAhash/sec range.

Your Pi would be trying to compete with the Thrust SSC in a max-speed race in your Model T Ford that has 2 cylenders not firing and thinking you have a chance of being competative.


 All current miners and most recent ones already have controllers built into them, no need for a Pi or similar to run them with.


 The Avalon 4.1 was LESS efficient than the Antminer S5, which was LESS efficient than the Spondoolies SP20 could be set up for (though the SP20 at stock settings was both a little faster and a little less efficient thatn the S5). I'd tend to ignore it unless you can get one VERY cheap ($200 or less + shipping).


 New miners have been anounced both by Lketc/BW and by Avalon - I'd wait a month or two for them to actually show up with real avaiability and pricing before I made a decision.

 Innosilicon also announced they achieved tapeout some months back on new gen SHA256 (A3) and Scrypt (A4) chips, and they have a history of building miners around their own chips - I expect to see something out of them at some point too, probably late this year or very early 2016.

 Partly correct. The fan usage DOES come out of one or more of those PCI-E connectors (I think it's probably split between 2 of them, but haven't pulled my SP20 apart long enough to actually check it).


 DON'T count on 1.7 TH - you have to have a very cold room to even have a prayer of achieving that. 1.3-1.4 TH range is achieveable easily even in somewhat warm rooms though, and is quite a bit more efficient to achieve.

 Do NOT under any circumstances try to run 2 connectors from one cable, unless it is a VERY custom cable with something on the order of 12AWG wiring.

 SP20 does not have wireless. Standard twisted-pair Ethernet only.

 The official spec on the MOLEX connectors that the PCI-E power specification uses works out to 288 watts per connector (the pins are rated more, but have to derate for use in that particular connector style).
 Exceeding this tends to lead to issues like the KnC Neptune and some Titans had with MELTED connectors and resultant fire and damage-to-unit risk.

 Most power supplies use 18AWG on their PCI-E connections - this is plenty for a SINGLE connector at 225 watts (per the PCI-E spec), it gets a bit marginal at 288 watts.

Why cap it?

 More sales should eventually drop the cost at least a little, and might help sell "extra" units on a non-trade basis for those of us that don't have "dead" S5s.

3BTC and availability in early December would be good. Would put some serious price pressure on BitMain's S7 and the upcomming Avalon 6.

 I KNEW I wanted to wait for around the end of the year before I jumped for a reason.

 8-)

Lower efficiency than the Antminer S7 or the announced 3TH Lketc/BW unit, though close.
Fan appears to be the same unit or a very close to the same unit as on the S5/S7, so NOT quiet (makes sense though at the given power level and form factor).

 This thing had better be priced lower than either the S7 or the eventual pricing on the Lketc/BW unit if Avalon expects to sell a significant number of them.


 I am NOT fond of the "auto speed" stuff, that's one of my bigger complaints with the Spondoolies SP20 - can't fine tune the thing yourself, you have to tolerate THEIR assumptions on how you want the thing tuned.

 38C max intake temperature - if that's for full hashrate, it's tolerable, but still kinda low. Seems like this unit could use better heat dissipation design work.


 what is a "golden power supply"? Is that supposed to mean a "Gold Efficiency Rated" power supply?

 The Gekkoscience Compac is more efficient than any other miner currently being sold to the public except for the S7 - and on the lowest undervolt settings the Compac can argue with an S7 on efficiency.

 U3 isn't even close - it's a generation older chip and doesn't undervolt nearly as much - the BM1384 in the Compac at it's HIGH voltage settings is more efficient.

.87 B per TH sounds more likely than .87 B per miner - but it would still be better pricing by quite a bit vs. the S7 and would be in the ballpark of having a prayer of RoI with cheap enough electric.

(does a quick visit to bitcoinwisdom)

 Hmmm, using my current "standard assumptions" this thing will barely achieve RoI (NOT including cost of PS or shipping) at my current 6.7 cent "incremental" electric rate, *IF* it goes on sale to the public at 0.87/TH soon enough to get delivered by 1 December 2015 and if the halfing does not happen before mid-July.

 TONS better than the S7 manages at it's current pricing, but still a bit marginal at best for most folks.

 They appear to be talking about the same miner that's been getting discussed in the LKetc thread for a month and some now, in the 3TH "bottom end" version from that thread.

 Keep in mind that BW is some sort of partnership/corporate deal between BitCoinBank and Lketc.


 On the plus side, it appears this miner might have a realistic chance to achieve RoI before the halfing renders it unprofitable - IF you have cheap enough electric and if it gets delivered by early December.
 I still can't say that about the S7 unless you're in VERY VERY cheap electric areas.

They appear to be talking about the same Lketc miners in the bottom-end 3TH version - this is NOT a bloody USB stick, whoever came up with that concept needs to go back to school and learn some basic math.

 The quote was in BTC, not $ - though even the quoted 0.87B per miner seems a little low even as a batch price, it WOULD be nice and competative and would make RoI on these things achievable!


 "per chip" does not specify "per miner".