BFL ASIC mining board project

[joeventura]

The DC/DC mosfets are a little hotter than I'd like, they're probably going to require airflow over them or heatsinks on the bottom side. We'll see once the production boards get here; there are layout improvements and a move from 1 oz to 2oz copper vs the prototype, so we might be able to avoid needing to heatsink them. With a couple small RAM heatsinks from an old VGA cooler I have on the underside, I'm seeing ~65C MOSFET temps, so cooling temp without deafening fan noise should be pretty trivial.

Not sure if you might wanna test the MOSFETs you're getting to make sure they actually meet the data sheet spec. Reading between the lines of BFLs (mis)adventures, it seemed like they had that issue. I've also heard rumors of counterfeit parts, meaning you think you got a big name 20A part and it's a remarked POS burning up at 5A.

As I recall the issue BFL had was that the boards traces were not hefty enough to handle the unexpected increased power requirements.

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[MrTeal]

Some videos. The first one is kind of a nominal load for the board. 107 hashing engines, setpoint of 283MHz per engine to give 30GH/s. Everything stays nice and cool, the board draws 130W at the wall. The cooler is a Hyper 212 Evo, and there's a couple little stick on GPU RAM heatsinks on the bottom under the mosfets, with a little quiet 80mm fan blowing towards them. The mosfets are 125F.
http://youtu.be/VOOGvlpNwws

This one is what I'd consider an overclock. 1.15V on the chips, with the same 283MHz nominal setpoint. 38GH/s and the mosfets got up to 175F. If you plan to do that constantly you'd probably want to invest in some proper cooling and airflow for them. Pulling 220W from the wall, so a big power penalty for those extra 8 GH/s
http://youtu.be/cCqiCodE12Y

I've found  1.1V on the ASIC to be a nice compromise for the future, with 35GH/s and 180W draw and things staying much cooler.

[yurtesen]

For people who are interested in MrTeal's soon to be ready boards and want to get the product soon, I have 96 chips worth of chip credits invested with original group board/chip buy, 1st and 2nd half of the payments paid. I am willing to sell my share for less than the price I paid in BTC. Basically you get the hardware for 1/4the price of what BFL sells so it is a big win.

I paid ~48BTC for 1st and 2nd half for 96 chip. I am willing to transfer my boards for 30BTC if you want all 96 chips... (this is hashing power equal to 6x 50gh units that BFL is selling for $2500 each, it is a bargain!)

If you are interested in using escrow (although it is quite trivial for MrTeal to transfer my purchase to you), I have put my slot on sale on Bitmit!
https://www.bitmit.net/en/item/61563-380gh-bitcoin-asic-miner-slot-for-35btc

You can PM me if you are interested (I can go even lower on the price but not much more) or buy from BitMit.

THEY ARE SOLD, THANKS FOR LOOKING

[MrTeal]

Since I posted up those videos the board's been going strong for two days at 35GH/s, drawing 180W at the wall.

More details on how purchases will happen will be released by tomorrow.

[Dagger75]

This new Revision of BFL chips w/ the metal layers seems to be able to hit higher Gh/s but still just as power hungry and hot! 

@MrTeal, how was the board running w/ that Watercooling loop you had on it?  Just wondering if it's worth picking up a decent closed loop system over a $30 120mm HS&Fan setup.  It it lets me get an extra 5Gh/s while being able to use a 80-92mm Fan to cool off the vregs and others circuits then I'd probably go for it on atleast one of my boards. 

Are the Sample chips you're using the new Revision chips by chance?  Do you notice a big difference in what Coolers you're using since they output so much heat?  And last question I promise, have you had any luck using a TIM as opposed to the heat pads?  Hope the newer chips are more uniform as that'd make cooling much more effective.

[MrTeal]

This new Revision of BFL chips w/ the metal layers seems to be able to hit higher Gh/s but still just as power hungry and hot! 

@MrTeal, how was the board running w/ that Watercooling loop you had on it?  Just wondering if it's worth picking up a decent closed loop system over a $30 120mm HS&Fan setup.  It it lets me get an extra 5Gh/s while being able to use a 80-92mm Fan to cool off the vregs and others circuits then I'd probably go for it on atleast one of my boards. 

Are the Sample chips you're using the new Revision chips by chance?  Do you notice a big difference in what Coolers you're using since they output so much heat?  And last question I promise, have you had any luck using a TIM as opposed to the heat pads?  Hope the newer chips are more uniform as that'd make cooling much more effective.

So far I've only used the rev A chips on boards. When the production boards arrive I will be mounting one with some Rev B samples. Efficiency actually isn't terrible right now; while 130W for 30GH/s isn't great that's a little under the sweet spot for my 850W power supply. I'll probably pick up a proper gold or platinum PSU once I get a moment, it should perform better than the plain brown box HEC PSU I'm running them on right now.

The closed loop cooler seemed to work ok, but I've only tried it with decent (as opposed to great) thermal pads. I took it off when I took the videos because I didn't want to give the impression that you need to use water cooling. Far more important than the cooler itself is the thermal interface between the two surfaces. While specs don't tell the whole story, the difference between a 0.25mm thermal adhesive tape like 3M's 8810 at 7.74°C*cm^2/W, versus the initial pads I was using (3.0°C*cm^2/W), vs something like the Fujipoly Ultra Extreme pads (0.4C*cm^2/W) absolutely dwarfs any differences between a good air cooler and a closed loop water cooler. I just really liked the water cooler since it moves the mass of cooler away from the board and makes probing test points easier.

I've actually had some good conversations with an applications engineer at Arctic Silver who has provided me some literature and samples on their products for my idea to bond a heatspreader to the ASICs so I can use a proper minimum bond line grease interface between heat spreader and cooler. Once the first production boards get built here in the next couple days I'll try that on the existing board I have to see what happens. The per chip temperature sensing is now being output out the debug UART (cg/bfgminer integration is still on the to-do list), so I'll be able to directly compare results between TIM+Hyper212 Evo, TIM+Water, and bonded heatspreader on the same board.

[Dagger75]

Very exciting stuff thanks!  I'm sure i'm not the only one looking forward to the incoming boards and your testing results.  I can't get enough of this good stuff and the GH/s is just bonus 

But, thanks again for your time and your work and Chipgeek as well.

I have a few decent HS&F I picked up for a great deal and may just go ahead and pickup a closed loop water-cooler if I can find a good deal.  Will be fun to see what they can do for sure.

[yurtesen]

I am selling my 96chip slot for 30BTC right now:
https://www.bitmit.net/en/item/61563-380gh-bitcoin-asic-miner-slot-for-30btc

As bonus, I can bundle 256 chip credits (although it is not mentioned on BitMit, after purchase you can send me your address to transfer the credits to).

THEY ARE SOLD, THANKS FOR LOOKING

[mmmerlin]

I am selling my 96chip slot for 30BTC right now:
https://www.bitmit.net/en/item/61563-380gh-bitcoin-asic-miner-slot-for-30btc

As bonus, I can bundle 256 chip credits (although it is not mentioned on BitMit, after purchase you can send me your address to transfer the credits to).

THEY ARE SOLD, THANKS FOR LOOKING

If anyone else is looking to buy - I have up to 248 chips on order that I would be willing to part with - PM with offers if interested.

[Photon939]

I haven't seen it mentioned in this thread but have you tried going for just paste and see what you get?

My BFL little single when it originally arrived would clock in at 31 GH/s  (which is pretty sweet for rev A chips) but after a few weeks only seemed to run at 30.6 GH/s.

I said screw it and cleaned off all the thermal pad gunk and applied Arctic Cooling MX3. It dropped temps by about 4C and has ratcheted up to 31.2 GH/s

[MrTeal]

I haven't seen it mentioned in this thread but have you tried going for just paste and see what you get?

My BFL little single when it originally arrived would clock in at 31 GH/s  (which is pretty sweet for rev A chips) but after a few weeks only seemed to run at 30.6 GH/s.

I said screw it and cleaned off all the thermal pad gunk and applied Arctic Cooling MX3. It dropped temps by about 4C and has ratcheted up to 31.2 GH/s

I want to wait until the new boards arrive (should be tomorrow) and get populated before messing with the hardware I have. I don't think it would ruin anything, but I don't want to risk frying chips.

[mmmerlin]

I want to wait until the new boards arrive (should be tomorrow) and get populated before messing with the hardware I have. I don't think it would ruin anything, but I don't want to risk frying chips.

I would have thought that just as a new batch of boards is about to be made up would be the perfect time to fry the old ones!

Joking aside though, perhaps just after the new ones are confirmed to be working would be the ideal time to try something with the old batch...

[Dagger75]

Just an FYI for those looking for decent and Cheap cooling for these boards, Newegg has this Zalman for $10 after $20 rebate http://www.newegg.com/Product/Product.aspx?Item=N82E16835118099

[Two4D]

MrTeal, Im still waiting for your reply..

[Nemesis]

Dang ppl, this project wont give you ROI.

Mr Teal, please looking into having bitfury mining board. Thats what i would buy. Dont waste time (money) into this. The longer delay in having bitfury the more btc you will not mine.

[kosmokramer]

If you're interested in this project and need chips at a great price, I have 100 available (shipping from BFL this week). The order is from 6/20/2013, so it should be much faster than buying from BFL directly at this point ... which means a lot, given recent difficulty increases.

PM ASAP with interest.

[volosator]

Can I mail in the chips and get them mounted on the boards?

[mmmerlin]

If you're interested in this project and need chips at a great price, I have 100 available (shipping from BFL this week). The order is from 6/20/2013, so it should be much faster than buying from BFL directly at this point ... which means a lot, given recent difficulty increases.

PM ASAP with interest.

Likewise, but with 248 chips. Again, PM if interested.

[MrTeal]

[Dagger75]

Sweet MrTeal!  Who is gonna be able to get boards from first batch?  Gonna be in order of order?      

BTW, waiting for mined BTC to finish confirms and will get the last 50% Chip payment out on Thurday.