Does anybody think that S2 is an intermediate product before Bitmain releases S3=S1 form factor with a different chip (40nm or 28nm)?
Can S1 form factor even work with 40nm or 28nm chip? I imagine that it could, perhaps with two fans (push-pull)?
I would be thrilled to have the S1 equivalent form factor, hashing at 400-500GH/s.
It would be a huge blockbuster if it will be as reliable as S1 has been (at least in most cases).
The thing is, a simple die shrink wouldn't help efficiency THAT much I don't think, they would nee to do a bit of redesign as well in order to get better efficiency, though a die shrink would help. They would need to go from 55nm to 20nm to stay competitive or give miners a huge incentive to buy within the next 6 months.
That said, I firmly believe that the S1 form factor is extremely important if BTC is going to succeed. The problem with having all these GIANT units is that they will only be held by small amounts of folks. I can convince friends and family and other people interested in mining to pick up an Antminer S1 at these current prices very easily, so in that sense, its awesome. However, the problem with these more efficient big boys is that they cost thousands of dollars.
If Bitmaintech could release a 20nm Antminer S10, or something like that, that was basically a 500 GH.S 20/28nm version with some efficiency and UI upgrades, and sell it for say, 2 btc, I think a lot of people would hop on board, and they could churn these out for at least 6-8 months.
going from 55nm to 28nm would improve efficiency by about 4x at chip level (perhaps more if they revise the design at all). The overall efficiency might increase by 3.5x to account for the power use of everything else in the BOM and the control modules
and you have to get over the idea that the S2 is 'too big'. The S1 cost 4.75BTC at first, now its about 15% of that price. The S2 is due for a pricedrop to a more realistic ~5BTC very soon if it want to stay relevant. This will drop to 3.5BTC after a month.
The biggest advantage in the S2 is some clear design improvements. these include: space for ATX psu, rack-mounting, denser chip arrangement, and 140mm fans (these are VERY good fans, more airflow than from the S1 fan but less RPM and noise)
If they come out with a new chip, I expect they will maintain the S2 profile, but pack in 4-5TH of chips.