Re: Diablo Mining Company will never buy Butterfly Labs hardware

What do you think that Kintex 7 480 would do Mh/s and Mh/W? Any insight into Artix 7s? They are supposed to slot into the Spartan 6 space once available in good volume.

I haven't tried mining on the 480s, only on V6 240s. The reason behind this is I have a handful of unused boards that have V6s on them, while the K7 boards are all used for my real work.

I made an entry in the mining hardware comparison long ago:

The V6 240s run at 375 MH/s at about 16w. This isn't optimized (other than to use some DSP48s), so I guess you could probably squeeze another 50-100 MH/s out of the devices with some effort.

The MH/s based on the size of the device breaks down as follows:

375MH/s / 240 = 1.5625 MH/s per "size unit"

Based on this, I would estimate the 480 could do:

480 * 1.5625 = 750 MH/s

I haven't used Xilinx's power estimator for a K7 bitcoin design, but Xilinx claims 50% less power than the V6.

So, you could assume your worst case would be 32w, best case 16w. Somewhere in the middle will probably be your actual power.

BUT!! You may think the Kintex 7 would be better for mining (price/performance) than a Spartan or Artix device, but you'd be wrong!

Take the Mod miner for example:

840 MH/s @ 40w in 4 x Spartan 150 devices

840 MH/s / (4 * 150) = 1.4 MH/s per "size unit"

So, the S6 is a little less efficient in terms of size/performance (partly because I used DSP48s in the V6 example to reduce logic usage, but there are other factors), but the price difference is huge. I think the S6 LX150 is ~$100, so there's no real good reason to buy the K7 or V6. The K7 and V6 provide more advanced functionality (high speed serial, more internal memory, more DSP slices, more pins, etc) that aren't required for bitcoin mining. You'd end up paying for features you don't use.

Once the Artix devices come out in force, I suspect they will be similar in price/performance to the S6. Power consumption will be somewhere between 50% less and the same as the S6. However, they are the last devices to go into production (after the K7 and V7).

Okay, so, the forum had V7 and K7 pricing a magnitude wrong (thanks guys), so what is the cheapest way of getting SASICS? Power usage isn't an issue if we go 65 or 90nm, and BFL is going 90 or 130nm on "real" ASIC (which has yet to be proven).

I think the ideal device would be an FPGA that it just all slices, no DSP slices, no high speed serial, no large gobs of memory, etc, and on top of that offers SASIC migration.

Does any company offer that, no matter the node size?

I am not that familiar with Structred ASICs (SASICs). I'm mostly a Xilinx person, and they offer "Easypath" devices which aren't Structured ASICs. They are more or less FPGAs that only load one bitstream. Xilinx only promises a 35% cost reduction and requires a 300K upfront fee. I don't believe Easy path devices are offered for the Spartan 6 family because the cost is already pretty low.

Altera offers actual structured ASICs for many families, so the price per unit can be reasonable for a larger device. However, since it's an actual custom ASIC, the setup/up front fee is probably pretty large. In addition, you have to budget time and money for "oops" mistakes which would require a second or even third turn of the ASIC.

Anyway, to answer your question, Altera offers 4 different structured ASIC options. Two of the options offer the stuff you would use for mining (mostly logic, not features we wouldn't use) without extra fluff. They also offer sizes that range from small to large within the different families.

I do not have any pricing information on this scheme because I've never gone down this path as part of my Job. I still think the cost is non trivial since you're actually making a custom device.

There are other vendors you can work with that will help you convert create and ASIC or Structured ASIC, but Altera offers an end to end solution for SASICs. That probably makes them a good choice since you only deal with one vendor. However, I have never dealt with that type of design flow before, so I have no first hand experience.

In the end, it's all about up front money. Upfront money for manufacturing a PCB (not too bad), and upfront money to create an ASIC or SASIC. I am curious as to what route (ASIC/SASIC) BFL went for their "upcoming" products and what the upfront costs were... Time to market for any of these options is pretty long, so they had to have started a while ago.