Edit: got it wrong by a few orders of magnitude. Corrected.

These guys have built a test chip essentially for testing SHA-3, but they also included an SHA 2 core:
http://rijndael.ece.vt.edu/sha3/sha3chip.html

The chip is just 5mm² using standard cells 130nm process, the SHA2 core is only a tiny percentage of that. Now look at the data sheet:

http://rijndael.ece.vt.edu/sha3/chip/sha3-asic-datasheet.pdf

Scroll down to page 14. For 512 bit blocks it says throughput is 1.51 Gbps @200 Mhz . Next page reveals a power consumption of 5mW.

So we are looking at 0.75 MH/s for 5mW ?

Scale that up and you get 750MH for 5W and still have a chip thats pretty damn small.

Just run only  two (if needed, underclocked  and undervolted) cards per case during the day, and run them all full blast past office hours.
its not hard to have a few cards run virtually silent if you compromise on density. Both of my machines are whisper quiet and my GPUs are all well below 60C. All you need is something like twin frozr cards or good after market coolers in a case thats reasonably well ventilated with lots of silent fans. With only 2 or so cards per rig, thats easy. Any half decent gaming case will do (I have an antec 300, its dirt cheap and plenty good for 2 cards).  Its not very power efficient, but you wouldnt care.

Actually, I do own one (or rather, half a plane). Just not one that make it all the way to thailand. And not enough room for luggage either. Not too mention the girlfriend would have to sit on the tail.  I hear 747s have dropped in price over the past years though .

Good thinking. I was just booking a flight to Thailand for December, but then it hit me; why not buy an airplane instead?

Although litecoin has a few actual advantages over BTC, the reason Im suggesting it is not that Im convinced it will take over the world. Its because bitminter's cpu mining speed is (no offense) useless, replacing it with litecoin mining would make it useful.

Litecoin price/difficulty doesnt make it hugely profitable but at least for now, certainly more interesting than namecoins. The fact it can be done with cpus and doesnt need drivers or highend amd cards, would also be a strong asset for any syndication deal that would target your miner to regular folks, rather than us nerds.

Me likes
Now, how about benchmarking some battle-fields 3

Jeremy, just a suggestion if you would reconsider a second attempt, I think some extra rules could make it work.

-1  disallow sniping. Very simple, set a deadline, but also allow bidding up to, say 1 hour after the last bet, even past the deadline. That way you dont get ebay nonsense with people trying to bet 1s second before the deadline.
-2 to make editing at least much more difficult, set a minimum bid increase and require people quote the previous winning bid. Okay, its not quite a secure bitcoin chain, but it should be good enough, particularly if mods can verify if needed.
-3 Disallow any edits (again hoping mods can check if there is any controversy).
-4 obviously, explicitly disallow a "maximum" bid.  You bid one number, and thats what you commit to pay.


I think with those rules, it could work. Not that Ill bid, unless you put an airplane ticket on auction too .

We want pictures!

You are killing it. Electromigration is eating your card. If you overvolt, stop it. And try to keep them cooler if you want them to last. 87C is really too much for 24/7.

30GB storage I assume. Is there a bandwidth limit?

Honestly, I think your current 1 BTC coins are far better suited for that. Its still cheap enough that you can give it away (certainly at current bitcoin prices), it looks terrific, the hologram adds some "mystery" "techno".. dont know what, sci-fi aspect to it, and its reasonably secure. Because of the tamper proof hologram and the public/private key, its also a good way to educate people. Having a visible private key and a good chance the coin is worthless, I think will only reinforce any impression that bitcoin is "dangerous" and potentially worthless.

So no, I wouldnt buy any. But Im pooling another purchase for a lot of 1 BTC coins.

Hmmm. same kind of what thing? Also not sure what a "bad sag" is, but now that you mention it, the burnt molex connector was on my mining rig and that was with an old rather crappy 450W PSU that only powers a single 5850 and a hdd. I have measured voltages (just with a multimeter) and they seem stable, but 12V is only ~11.6-11.7v under load.

If you meant to ask if there could be  a relationship with my desktop where the 4 pin fell out; no, none. Different machine, and this one has a nearly new Zalman 650W thats working perfectly.

Excuse me for interrupting you guys, but now that we finally have a few people who seem to know a thing or two about FPGAs, care to share your thoughts on this Butterfly Lab product? Feasible, unfeasible, scam or not, fpga, not fpga, asic, hybrid something else?

How are your temperatures now? I have a sapphire 5850 that uses the same fan (or at least looks a lot like it), and it has a design that seems created specifically for blowing air sideways, rather than only down. I had already wondered how well or how  bad a traditional fan would work in there, so did you notice any increase or decrease in temperatures? Noise?

Any decent PSU should have short circuit protection, so Im not sure thats it.

Just a wild guess, Ive had a motherboard where that 4 pin ATX connector doesnt lock in to place. The "lid" is only in the middle and locks the 20 pins, but not the extra 4 pin if you PSU has a 20+4 pin connector like that. If its not securely put in place, it could loosen itself and bad things might happen.

Actually just a few days ago I pretty much had that exact issue only with a 4 pin cpu connector loosening itself (PSU has 2x4 pin for CPU, motherboard only 1x4 pin, and both PSU leads fit, and work, but only one "clicks". I had used the wrong one). Out of the blue my computer shut down and would no longer boot. Turns out that connector came came lose. Luckily nothing was damaged, but I imagine had it been pulling 20+A and release slowly, it could have turned in to a lightshow.

https://bitcointalk.org/index.php?topic=28402.msg620360#msg620360

Also applies if you are not running a GUI.

Per core
Each core using 7% of their FPGA. WHich is a virtex 2, stone age FPGA.
The point here is not absolute performance, that document is I believe 6 years old,  the point is using a GPP they achieved significant speedup (actually, die size savings which can be used for the same) over partially or fully unrolled pure fpga approaches. I think that validates that a hybrid approach can work.

Anyway, Ill just leave it at that, and we shall see in a few weeks.

Yes, Im aware (I do have large feet ). But in the case of SHA hashing both the while/do loop and your "print" statement is slightly more complicated, and I do not see why it could not be beneficial to optimize chips for specific tasks. To use your example, you could have one FPGA that only does "print i"'s, but is very efficient at it and can be clocked very high and do a lot of them in parallel;  and one chip that feeds it the "i"s and does all the control logic, but has to be clocked at lower speeds.

If you think that sounds silly, have a look at this paper:
http://ce.et.tudelft.nl/publicationfiles/1194_657_SHA2.pdf

They seem to do precisely that, separate a small critical path of the hashing function in to SHA coprocessors that are fed by a (virtual) PowerPC core, in this case, implemented on the same FPGA as the coprocessors. It doesnt take too much faith to imagine it makes more sense to use an actual PowerPC chip or some other GPP to feed 32 FPGA's with "print i" instructions.

Dont know TBH. I gave up on windows once I discovered that linuxcoin has no problems overclocking beyond the hardcoded "safe limits". That was the only reason I tried windows. I think getting rid of CCC is all you need to do, but I havent tested it.

Because different chips are good at different things. I know AMD drivers use the CPU to unroll shader loops before sending them to the GPU. I assume they have a reason for that, and latency isnt killing them (even if game rendering is probably by itself far more latency bound than hashing. Its no good having 100FPS if they lag 1 second ).

I wouldnt be one bit surprised if it turns out the BFL "rig box" has some CPU or asip for that very purpose, and the single boards do not.


Yes, but probably  slower.



No, the issue is that implementing the unrolling logic costs a lot of die space and limits clocks.  For all I know it might make sense to have one FPGA do only or mostly unrolling, and one, running at higher clock speeds, only hashing. What Ive read is that using 50% die space for the unrolling is fairly typical, so using 50% of the chips could make a lot of sense.  Never wondered why even the "single" board has 2 FPGA's (assuming thats what they are) ?


Agreed .