Last week somebody was saying they thought bitcoin is the "most efficient" way to pay, so I crunched some numbers to find out. Summary: it is not.

Currently 262 Terahash/s=262E12 hash/s
Most efficient bitfury hardware gets 705E6 hash/J, or 1.42E-9 J/hash ==>Note I'm being as conservative as possible here, in BTC's favor

So total network power consumption is at least (1.42E-9 J/hash)*(262E12 hash/s)=372040 J/s = 372 kW. Like I said, this is the most efficient scenario, with little room to improve with new mining hardware in the future. A year ago it was far, far worse.

36944 bitcoins change hands/hour, on average.
(3600 seconds * 372040 J/s)/($100/btc*36944 btc/hour)=362 J/$ processed.

Now let's compare to Visa. Visa processes avg $6.7T/year= 6.7E12 $/y = 212456 $/second. If Visa consumed as much power as bitcoin, that would be (362 J/$)*(212456 $/s)= 76.9 MW of power.

Visa has 2 datacenters in N America, consuming about 25MW each. And that includes stuff like AC, that I didn't even consider for bitcoin. So Visa actually uses far less energy/$ than bitcoin. And bitcoin is getting less efficient every day as the hash rate grows.
http://usatoday30.usatoday.com/tech/news/story/2012-03-25/visa-data-center/53774904/1

Discuss.

I'm sure this idea has been tossed around before, but I think it would be really great. How about a small block every, say, 10 seconds? Then you don't have to wait an hour to get a transaction confirmed 6 times. You would only have to wait a minute.

Are they any serious reasons why this can't be implemented? The only 2 I can think of are:

1. Block chain history gets too big, becoming a memory issue.

If so, we could start "forgetting about" the older end of the block chain. From what I understand, this would cause unused coins to be deleted. Well, that would be an interesting dynamic! Encouraging people to spend instead of holding for years and years.

2. Bandwidth limitations

This is an effort to bring together ideas of a cheap, simple, robust communication interface for FPGA mining boards. Eventually we want to use it on our FPGA Board.

My current idea is an FS232 chip. So- serial in to configure and send data to the chip. You would need to use an output from the chip to send data back, which would use up a few chip resources (that's the downside). I think we might even get away with no voltage level shifter

[$440 equivalent based on the MT Gox weighted average]

I have been working with 2 other members of the bitcoin community to develop a custom FPGA mining board. Our goal was a quiet, efficient, highly profitable platform for bitcoin mining… with a much lower pricetag than previous FPGA boards.



We have made and tested a prototype with pool mining. With the most recent program it gets 100 MHash/s and uses 6.8W of power. In the future we expect incremental improvements to the mining speed due to better software. You can see from the Mining Hardware Comparison that our custom board is far better than the commercial FPGA alternatives in terms of $/Mhash.

The primary members of this FPGA team were:
fpgaminer, USA, Engineer
li_gangyi, Singapore, Electronics Hobbyist
newMeat1, USA, Engineer

We also want to thank makomk for his contributions to optimizing the code and NF6X for his advice on communication interfaces. It is a testament to the global nature of the bitcoin community that we were able to bring together such great talent from across the world.

Check out Li’s blog on the development of the board for more pictures!

We have 4 boards for sale at this moment. The cost is $440 equivalent based on the MT Gox weighted average, to be paid in BTC. Shipping costs will be added. We do international shipping—please message me if interested and we’ll work out the details. Up-front payment is required to cover our hardware costs. The boards will ship within 7 days after receipt of payment.

In the next few weeks, we will be putting together a bulk order, so don’t worry much if you miss out on this initial batch.

What do you need to run these boards on your computer?
•   An open USB port
•   An open 4-pin Molex power connector. Most computers have an extra one or two of these inside (my PC has 4!)

•   Download and install Xilinx's free ISE software, here
•   A Xilinx Platform Cable- we recommend eBay to get it cheap
•   Operating system: Windows, Red Hat Enterprise Linux WS and SUSE Linux Enterprise are supported
o   Other versions of Linux may work, but no guarantees

We'll be posting a walk-through soon about how to set up the board. If you got the bitcoin client running, you shouldn’t have any problems setting up the FPGA board  

Get yours now- the Bitcoin Dominator X5000!

I had a link in my signature before- no problemo. But now it's not working... Did I make a fat-finger mistake?

This is also the same time that I  went from being a Jr. Member to a Full Member. Probably doesn't have anything to do with it, but you never know

Highlights are Civ 5, Left 4 Dead, and Half-Life 2 Orange Box. I'm in good standing on everything

I'm moving so I have to get rid of this stuff. I'm in the Mukilteo area, north of Seattle. PM me if interested and I will give you my address for pickup. Must be picked up before Sat 7/30

Nice desk, 1.5BTC:


White desk, free if you want it with the first desk. Otherwise it goes to Goodwill


Little Ikea corner table, also free if you want it with the first desk

Hello,

I can't offer much more than 1 BTC but I would be much obliged if an FPGA guru would help solve my JTAG issue for an FPGA.

The problem comes when I try to program my EP4CE75F23 with Quartus Programmer. I get an "Error: Can't access JTAG chain" message.

If I go into the JTAG Debugger tool, I can run an automatic test on the JTAG. This is the result of that test:

It's interesting that it recognizes the chip as an EP3C80.

I can also step through the JTAG state machine to see if the JTAG header pins cycle. TDO and TMS cycle from 0 to ~2.5V as expected. TDI is stuck low. TCK is stuck high.

I've gone through and double-checked that my JTAG-related pins are connected like pg 46 of this document:
http://www.altera.com/literature/hb/cyclone-iv/cyiv-51008.pdf

I've got no reason to suspect that the chip was harmed, and the soldering looks good. All of the bus voltages are good as well. I'll check the clock input to the chip with an oscilloscope later today, but I'm pretty sure it's good, too.

I'm skeptical of my USB-blaster, because I bought it cheap on eBay. It may not be working right. That would explain why TDI is stuck, but I don't think it explains TCK.

To all the smart people out there- thanks in advance.

I want to get a little more liquidity at CampBX. I also see a chance to make some long-term Bitcoins here...

I will send you .02 BTC if you use the link in my signature to register at CampBX. You need to send me a screenshot of the "SUCCESS!" page (see Bal3wulf's example below). I need to be able to see your new username for CampBX as well as the user count at the bottom, so I can tell that it's legitimate.

It's a win-win-win situation. You get a 10% discount on trades, I get a small commission from CampBX, and they get more members. They are a new, secure and professional Bitcoin exchange, which is why I support them.

You can PM me this screenshot or post it here, along with your BTC address. I will take you at your word that you used my code.

Keep in mind, CampBX only works with dwolla transfers right now. They say they are adding European transfers soon. If you are outside of North America/Europe, CampBX probably won't work for you.

This holds for the first 25 replies I get. I'll post again when I've gotten all 25. Thanks
I get. I'll post again when I've gotten all 25. Thanks

I want to get a little more liquidity at CampBX. I also see a chance to make some long-term Bitcoins here...

I will send you .02 BTC if you use the link in my signature to register at CampBX. You need to send me a screenshot of the "SUCCESS!" page (see Bal3wulf's example below). I need to be able to see your new username for CampBX as well as the user count at the bottom, so I can tell that it's legitimate.

It's a win-win-win situation. You get a 10% discount on trades, I get a small commission from CampBX, and they get more members. They seem to be the most secure and professional Bitcoin exchange, which is why I support them.

You can PM me this screenshot or post it here, along with your BTC address. I will take you at your word that you used my code.

Keep in mind, CampBX only works with dwolla transfers right now. They say they are adding European transfers soon. If you are outside of North America/Europe, CampBX probably won't work for you.

This holds for the first 25 replies I get. I'll post again when I've gotten all 25. Thanks
I get. I'll post again when I've gotten all 25. Thanks

After a lot of thought, I've decided to release my FPGA files. I've put a lot of time and effort into designing a minimum-cost FPGA board. I've been through 2 prototype cycles, but this stuff is expensive! On my student budget, I can't afford to spend any more on a project that may or may not pan out. When I burned out my last Cyclone IV, I was like, "I'm done!" The design is 98% there, I believe.

Thanks to fpgaminer for lots of advice.

Here's a link where you can download a zipped folder. It contains pictures, a Bill of Materials with cost breakdown and suppliers, a circuit board layout, and links to all of the Altera documentation I've been using.
http://www.filedropper.com/pcbtoupload62611

You will need to download expressPCB's free CAD software to view the board layout. I hope that knowledgeable people with deep pockets can take this project and finish it. GPU mining is way too wasteful. There are probably still bugs in this design.

I used a Cyclone IV EP4CE115F23C8N FPGA. It offers good performance for a decent price. We have already hit 80 Mhash/s with it, with no cooling other than a passive heat sink. The heat is the limiting factor. With better cooling, we'll be able to add a second core and run it faster. I'm thinking ~140 Mhash/s.

As you can see, the board is very small. It would be very cool to make a cast aluminum box for it and fill the box up with mineral oil. That would give 100% reliable, cheap, quiet cooling. This guy may be able to hook one up:
http://forum.bitcoin.org/index.php?topic=20404.0

Feel free to send a few bones my way if you like the project!

A little prediction...

Long term, if bitcoin users can't be taxed, governments will have no choice except to start charging absurd amounts for electricity. We have to pay for roads somehow.

I got a new graphics card to start mining with. I was hoping that I had a second slot to keep this old card, too... but I open the case and see that I don't.

It's an ATI Radeon HD 5450 PCI Express 2.0x16. It gets about 11.2 Mhash/s (not much, it's probably not worth buying to mine with). I wanted to use it as a backup to the powerful card, so that I could surf the web or game while mining. Some advantages are
1. it's quiet
2. it won't put much load on your power supply

It's about 1yr old. Only mined with it for about 3 days

I'm mining in Slush's pool, getting a measly 11Mh/s. It seems strange that I bring in larger rewards when the round drags on for a really long time, like an hour or more.

Shouldn't I earn more on short rounds, because the pool is taking in more BTC faster?

I bet that 20 or so people own over 1,000. Maybe a few pioneers own over 10k. Is that about right?

I'll be moving to another state soon. When I turn on my computer there, will my bitcoin wallet be all messed up? For example, maybe my IP address changes, and that changes my bitcoin address?

All offers considered. These are some great books, and they're cheap:

**The Road, by Cormac McCarthy, paperback, in pretty good shape (read like 4 times), 0.5 BTC

**Men are from Mars, Women are from Venus - hardcover, old, not in great shape, 0.5 BTC

**The Games People Play, by Dr. Eric Berne, old but still in decent shape - Sold

**2 Stephen King books:
The Colorado Kid, a great little mystery, paperback
Under the Dome, a 1074-pg novel, paperback, in great shape (only read once)
Selling these 2 together for 2 BTC. Cost is more because they're worth more and Under the Dome will cost a lot to ship

**What is the What, by Dave Eggers, paperback, only read once, it's about the Lost Boys of Sudan, 0.5 BTC

**Down and Out in the Magic Kingdom by Cory Doctorow, a great sci-fi author. This book is out there. Paperback, in decent shape, 0.5 BTC

Message me if interested and I'll give you my payment address

I'm selling a laptop through eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280679482246&ssPageName=STRK:MESELX:IT

Going through eBay is smart to protect both the buyer and the seller. We'll avoid PayPal by marking it as "Payment Received".