KnCMiner will today announce Neptune, its next-generation product: an ASIC bitcoin miner using 20nm chips that will provide at least 3TH of power.

The new boxes, which will ship “end of winter/early spring”, according to co-founder Sam Cole, will offer 0.7 watts per GH/sec. That represents a 30% power saving on its current generation of 28nm chips, he said.

KnCMiner’s

marketing model is conservative. It publishes nominal specifications for its devices ahead of time, with the caveat that these will probably be at the low end, and that real-world performance will be higher. It promised 400GH/sec for its 28nm Jupiter device, which eventually delivered 550-576GH/sec.

Cole is taking the same approach with the new box, saying that its 3TH performance is a minimum figure. He is also questioning the competition’s ability to deliver the performance promised with their 28nm boxes.

HashFast’s last update (at the time of writing) showed it had received silicon wafers with its circuitry (specced at under 0.65 watts per GH/sec) etched on them, and yet it originally promised shipments by late last month.

Cointerra said it had taped out its chips earlier in the month. HashFast is promising 1.2TH/sec per box for $6,300, while Cointerra is promising 2TH/sec for $5,999 (formerly $13,999). Cole said:

This box – the price of which hasn’t yet been revealed – will come with a caveat, though. Cole believes that residential power supplies in some households won’t be able to handle it on a single fuse. “American houses don’t have the same supply as Sweden or Germany for example,” he said.

“The issue is that we are getting very close to the limit of the household supply in our next generation,” he said. “So the bottleneck has become the house.” This will probably be one of the firm’s last retail products, he added.

All boxes would ship with broadly the same configuration, he said, although there may be some tweaks available on the site’s pre-ordering system.

Some North American users might not be able to use the full power of the boxes unless they run electrical supply from different fuses.

“Maybe a European house can run six chips and a US house less chips,” he said, adding that chips would turn on automatically as more power became available to the box.

This sounds counterintuitive – lower process nodes are supposed to draw less power on a per-chip basis, not more. But Cole argues that while the chips draw less power, they will be able to “squeeze more cores” into the box.

The firm will engineer more silicon onto a board to improve the overall performance of its mining product.

The 20nm chips will be fabricated by the firm’s current ASIC fabrication partner, TSMC. He said that the non-recurring engineering (NRE) cost for the chips would be around three times that of the 28nm device (this came in with a total NRE of $4.7m, although not all of those costs were attributable to TSMC).

These are bold claims in a bitcoin mining market already struggling to make profits as difficulty skyrockets.

But KnCMiner does have a good track record up its sleeve. The company delivered its first-generation products to schedule. He added:

The company has also succeeded where others have struggled in the hosted mining market.

KnCMiner has its own hosting operation, while Coinlab-funded hosted mining firm Alydian is in bankruptcy. Cole suggests that KncMiner’s hosted operation could be a good option considering the expected high electrical draw of the 20nm boxes.

Existing customers will get a discount on the boxes, and they will also receive their products around two or three weeks earlier than the competition. There will be no trade-in program.

Pre-orders open today, Cole said, adding that all specifications given to CoinDesk are pre-release and subject to change.