Cairnsmore1 - Quad XC6SLX150 Board

[DiabloD3]

I'm not arguing that a super high density board would be the ultimate in high density mining. Point is there is a sweet spot for a distributor between low volume sales and profit. With this board design they can make a high volume of boards, and reduce their per-unit overhead. Meaning better profit margins. A super high density board would allow better density, but would likely have much lower sales volumes (requiring thicker markup to make back their R&D overhead and such). Also manufacturing yield is easier to control on smaller boards.

Wrong. These manufacturers are already building 8x and 16x boards at _less_ cost per FPGA. Manufacturing largely has a problem where the cost of manufacturing a populated board effectively costs the same no matter how big the board is. In our case, a 16 FPGA board is not going to cost significantly more to manufacture than a 4 FPGA board.

Lastly, customer hardware failures are mitigated more with many small boards versus one large board. (if you blow a couple FPGAs on your 64x FPGA board what do you do about it?)

Who said 64x board? I said 64 FPGAs in 4u. Thats four 16x boards in 4U.

My ideas are purely within the confines of the cairnsmore1 product. How to pack as many into a rack as possible. Not a hypothetical new board. (enterpoint has said they may consider additional boards later depending on the success of the cairnsmore1, for now this is what we have to work with).

That said, you have a very good point about card height. Looking again at the mechanical drawings, once you consider motherboard thickness, connector height, and raised MB plate thickness the board likely won't fit in a 3U. (it would be damn close though, 3U is 133MM but internal space will be less, this board is 126.4 so likely won't fit in the end).

But I don't see why you think a "blade server" type approach is inappropriate? It offers high density (at least close to that of a super high-density board) and it offers modularity, easy maintenance (swap boards out), lower risk in the event of failure, and most importantly to many, smooth scalability (easy to keep buying small volumes of boards and expanding rather than having to drop $30K at a time).

Its an unusual design and connectors love to break off of boards. Its not a good idea and it costs money. There is the exact same risk in the even of failure: some of your FPGAs stop working.

Now considering 4U cases, an ideal option would be something like http://www.newegg.ca/Product/Product.aspx?Item=N82E16811165475
Remove the motherboard mounting plate, and mount the power supply where the 3x 5.25" bays are in the front. That would allow a full case width and a flat mounting surface in the back for the cards. You can easily fit 8 cards wide with plenty of room for heatsinks, and should be able to fit 2 cards deep in that config. This gives the same yield of FPGAs/U that your idea has, but is overall cheaper (1U rackmount cases are more expensive generally. or custom rackmount enclosures are also expensive, meaning per 1U you would be looking at probably $200-$300 per case if you include a power supply, making for $800-$1200 per 4U) in my setup that's $300 for a 4U case, $200 for PSU, so $500 total in case cost per 4U, same total number of FPGA, and I still have room to grow in the front half of the case (could always remove the hotswap drive cage and mount more cards up there, or have room for an added controller for standalone mining or whatever).

I think considering these cards specifically, that type of solution is the best way to go. Too bad it's so close to the 3U spec. If it would fit in a 3U that makes it more dense, which is even better.

Why are you so intent on essentially hacking this up like an idiot? Thats expensive to mass produce, stop that.

Lets try to figure out the total cost of making these the napkin way, and a quad costs $640 to buy.

My way:
per 16 FPGA/1U: $2310 for a 16 FPGA board, $90 for a Norco case that fits EEB and has 5 40mm fans, $50 for a Athena Power 1U 300w PSU
total cost per 4U: $9800 for 64 FPGAs, or $153 per FPGA
if something goes wrong: I lose 16 FPGAs minimum and maximum.


Your way:
Impossible to calculate because you're talking nonsense. What rack mountable case is going to fit 24 inches of cards? And don't say "just make a 8 FPGA 24 inch card" or something. The reason I specifically picked PCI-sized boards is because it is cheaper to produce PCI-sized boards due to the entire industry based around making them.

So, sure, lets use rainbows and unicorns and say you can fit 24 inch cards in cases that are somewhere around 23 to 31 inches deep inside without modifying the case (removing unused drive bays COSTS MONEY, changing the case design at all COSTS MONEY). And each one of those cards costs about, oh, $1220 to produce, and you can fit 7 cards in there, so thats $8540 for 56 FPGAs, plus who knows what for some controller board (lets say $100) because you just really really want one instead of just using SATA plugs like BFL did for the minirig.

per 56 FPGA/4U: $8540 for 7 56 FPGA boards, $100 for a board that does nothing but route serial connections, $70 for a Norco 4U case that fits EEB and has 2 80mm fans (and we need more than that so theres even more money wasted), and $160 for a NZXT Hale 90 750.
total cost per 4U:$8870 or $158 per FPGA.
if something goes wrong: You lose 8 FPGAs minimum, 58 maximum.

So not only do I get more density per 4U, my solution comes in cheaper.

[1713911811]

1713911811

[1713911811]

1713911811

[1713911811]

1713911811

[1713911811]

1713911811

[Glasswalker]

Impossible to calculate because you're talking nonsense. What rack mountable case is going to fit 24 inches of cards? And don't say "just make a 8 FPGA 24 inch card" or something. The reason I specifically picked PCI-sized boards is because it is cheaper to produce PCI-sized boards due to the entire industry based around making them.

So, sure, lets use rainbows and unicorns and say you can fit 24 inch cards in cases that are somewhere around 23 to 31 inches deep inside without modifying the case (removing unused drive bays COSTS MONEY, changing the case design at all COSTS MONEY). And each one of those cards costs about, oh, $1220 to produce, and you can fit 7 cards in there, so thats $8540 for 56 FPGAs, plus who knows what for some controller board (lets say $100) because you just really really want one instead of just using SATA plugs like BFL did for the minirig.

per 56 FPGA/4U: $8540 for 7 56 FPGA boards, $100 for a board that does nothing but route serial connections, $70 for a Norco 4U case that fits EEB and has 2 80mm fans (and we need more than that so theres even more money wasted), and $160 for a NZXT Hale 90 750.
total cost per 4U:$8870 or $158 per FPGA.
if something goes wrong: You lose 8 FPGAs minimum, 58 maximum.

So not only do I get more density per 4U, my solution comes in cheaper.

I'm not sure where you're getting the 24" card thing from?

I'm not trying to be an ass, I just think we're perhaps arguing 2 different points. You seem to be arguing the "best case optimal high density mining" solution, and I'm talking about "How can I best mount the cairnsmore1 cards in a rack".

I'm planning on mounting them similar to this:
https://bitcointalk.org/index.php?topic=70611.msg844733#msg844733
(that's my current icarus setup)

But using a 4U actual rackmount case rather than a wooden 3U case.

Mounted vertically the cards will need about 2" wide, a rackmount case is about 17" wide on the outside (so at least 16" - 16.5" of usable inside room side to side) and about 14" deep for the motherboard compartment (12" - 13" for the actual motherboard plate). These cards are like 6" - 7" deep so I can stack 8 of them side by side, 2 deep in the same arrangement I have in that photo. Filling the back of the case (like I said redirect the powersupply to the front of the case in place of the 5.25" drive bays).

This gives me room for 16x cairnsmore1 cards in a 4U rackmount case, with tech available right now (not a hypothetical future product). so a total of 16 FPGAs per Unit of rack space.

I'm not talking about an "optimal end solution for best case high density bitcoin mining" that's obviously going to require some higher density special purpose hardware, like the Merrick3 adjusted for higher power density, and put into a standard PCIe motherboard. OR the Merrick1 modified for a few less chips (maybe half, like 50 chips) and higher power density. I agree completely, a 100% custom 1U case with a custom board (or boards) holding a lot of chips will result in the best density. But that product doesn't exist, and won't exist for at least a few months (and that's if someone starts working on it right now).

The cairnsmore1 will be available in a couple weeks, so I'm talking about the best way to mount THOSE boards in a rackmount enclosure.

Also to note, I'm not talking about custom cases. I'm talking about an off the shelf case, which has removable drive cages already, you just unscrew it and remove it. Problem solved. Sure you need some custom brackets/clips to mount things, not a problem. That's what a 3D printer is for

Also yeah I planned on using the HALE90 as well in my build.

Does that make a little more sense?

[DiabloD3]

Impossible to calculate because you're talking nonsense. What rack mountable case is going to fit 24 inches of cards? And don't say "just make a 8 FPGA 24 inch card" or something. The reason I specifically picked PCI-sized boards is because it is cheaper to produce PCI-sized boards due to the entire industry based around making them.

So, sure, lets use rainbows and unicorns and say you can fit 24 inch cards in cases that are somewhere around 23 to 31 inches deep inside without modifying the case (removing unused drive bays COSTS MONEY, changing the case design at all COSTS MONEY). And each one of those cards costs about, oh, $1220 to produce, and you can fit 7 cards in there, so thats $8540 for 56 FPGAs, plus who knows what for some controller board (lets say $100) because you just really really want one instead of just using SATA plugs like BFL did for the minirig.

per 56 FPGA/4U: $8540 for 7 56 FPGA boards, $100 for a board that does nothing but route serial connections, $70 for a Norco 4U case that fits EEB and has 2 80mm fans (and we need more than that so theres even more money wasted), and $160 for a NZXT Hale 90 750.
total cost per 4U:$8870 or $158 per FPGA.
if something goes wrong: You lose 8 FPGAs minimum, 58 maximum.

So not only do I get more density per 4U, my solution comes in cheaper.

I'm not sure where you're getting the 24" card thing from?

I'm not trying to be an ass, I just think we're perhaps arguing 2 different points. You seem to be arguing the "best case optimal high density mining" solution, and I'm talking about "How can I best mount the cairnsmore1 cards in a rack".

I'm planning on mounting them similar to this:
https://bitcointalk.org/index.php?topic=70611.msg844733#msg844733
(that's my current icarus setup)

But using a 4U actual rackmount case rather than a wooden 3U case.

Mounted vertically the cards will need about 2" wide, a rackmount case is about 17" wide on the outside (so at least 16" - 16.5" of usable inside room side to side) and about 14" deep for the motherboard compartment (12" - 13" for the actual motherboard plate). These cards are like 6" - 7" deep so I can stack 8 of them side by side, 2 deep in the same arrangement I have in that photo. Filling the back of the case (like I said redirect the powersupply to the front of the case in place of the 5.25" drive bays).

This gives me room for 16x cairnsmore1 cards in a 4U rackmount case, with tech available right now (not a hypothetical future product). so a total of 16 FPGAs per Unit of rack space.

I'm not talking about an "optimal end solution for best case high density bitcoin mining" that's obviously going to require some higher density special purpose hardware, like the Merrick3 adjusted for higher power density, and put into a standard PCIe motherboard. OR the Merrick1 modified for a few less chips (maybe half, like 50 chips) and higher power density. I agree completely, a 100% custom 1U case with a custom board (or boards) holding a lot of chips will result in the best density. But that product doesn't exist, and won't exist for at least a few months (and that's if someone starts working on it right now).

The cairnsmore1 will be available in a couple weeks, so I'm talking about the best way to mount THOSE boards in a rackmount enclosure.

Also to note, I'm not talking about custom cases. I'm talking about an off the shelf case, which has removable drive cages already, you just unscrew it and remove it. Problem solved. Sure you need some custom brackets/clips to mount things, not a problem. That's what a 3D printer is for

Also yeah I planned on using the HALE90 as well in my build.

Does that make a little more sense?

It makes more sense, but it makes less economical sense. In the long run, I only care about cost per FPGA, and a 16x board should cost less than four 4x boards or eight 2x boards or whatever.

[Glasswalker]

It makes more sense, but it makes less economical sense. In the long run, I only care about cost per FPGA, and a 16x board should cost less than four 4x boards or eight 2x boards or whatever.

I agree completely, but only under the circumstance that the "better" option is available immediately (or available at a MUCH better cost/performance ratio)

If I have funds to buy say 8U filled with Cairnsmore1 right now (32 boards) and they are available in the next 30days, yet it would be 2-3 months before even the possibility of a higher density better solution, I'd rather be mining for that 2-3 months on the slightly less optimal Cairnsmore1 option, and re-evaluate when the available options change.

Also considering the smaller boards let me grow in a more fluid fashion, I can increase my hashing power in a fairly aggressive curve.

IE: 32 boards at 4x FPGA each, lets just for round math assume 800MHash even per board. So 25.6Ghash from that cluster, that lets me mine around 475BTC per month at current difficulties. That 475 can be re-invested in roughly 2 more boards (At the inflated "full" price). those 2 new boards generate about 30BTC a month, So month 2 I have 505BTC, buy 2 more boards, then I have 60 spare next month (plus the 30 from previous month) buy 2 more, now I Have 90 spare, plus the 90 from the previous 2 months, now that's 180 on top of the base 475, which buys me 3 boards. and so on. Typical exponential growth curve, allowing me to add quite a bit more hashing power in the timeframe it would take just waiting for the new boards to possibly come out.

I realize my math above may be skewed or off (it's all off the top of my head) But I've also done forecasts based on this (with real numbers in extensive spreadsheets). Looking at smaller boards versus larger boards with slightly higher performance/$ ratio, and the smaller boards won out in longterm ROI. (because they grew faster due to the fluid expansion). Especially when the larger option wouldn't be available initially for some time.

This is of course offset if the higher end board is much lower cost per MHash but I would be surprised if doing a much larger board dropped more than 10-15% off the price per chip. (just personal opinion though lol so take with a grain of salt)

[yohan]

First picture of the first manufactured Issue 1.1 now on http://www.enterpoint.co.uk/cairnsmore/cairnsmore1.html.

On stacking the boards the initial shipments will have a 33mm high heatsink which with thickness of chip, fan and fixings makes about 60-62mm above board surface. Add about 5mm for board thickness and rear solder joint protrusion. Probably add 10mm+ above fan to let air flow and you get your simple stacking height of about 80mm. After the first 100 units the heatsink is 10mm lower.

The fan can also be removed and used for side blowing if you really want to pack them in and if you really want to keep them cooler use a push pull fan arrangement. In this way you might get down to a 40-50mm stack spacing. With the right r/a bracket, and suitable stack spacing, the fan holes on the PCB can be used to hold on 120mm side fans in a stack.

[Glasswalker]

Excellent, I was hoping for 2" (50mm) or less spacing (without fans, I'll be using push/pull)

[DiabloD3]

It makes more sense, but it makes less economical sense. In the long run, I only care about cost per FPGA, and a 16x board should cost less than four 4x boards or eight 2x boards or whatever.

I agree completely, but only under the circumstance that the "better" option is available immediately (or available at a MUCH better cost/performance ratio)

If I have funds to buy say 8U filled with Cairnsmore1 right now (32 boards) and they are available in the next 30days, yet it would be 2-3 months before even the possibility of a higher density better solution, I'd rather be mining for that 2-3 months on the slightly less optimal Cairnsmore1 option, and re-evaluate when the available options change.

Also considering the smaller boards let me grow in a more fluid fashion, I can increase my hashing power in a fairly aggressive curve.

IE: 32 boards at 4x FPGA each, lets just for round math assume 800MHash even per board. So 25.6Ghash from that cluster, that lets me mine around 475BTC per month at current difficulties. That 475 can be re-invested in roughly 2 more boards (At the inflated "full" price). those 2 new boards generate about 30BTC a month, So month 2 I have 505BTC, buy 2 more boards, then I have 60 spare next month (plus the 30 from previous month) buy 2 more, now I Have 90 spare, plus the 90 from the previous 2 months, now that's 180 on top of the base 475, which buys me 3 boards. and so on. Typical exponential growth curve, allowing me to add quite a bit more hashing power in the timeframe it would take just waiting for the new boards to possibly come out.

I realize my math above may be skewed or off (it's all off the top of my head) But I've also done forecasts based on this (with real numbers in extensive spreadsheets). Looking at smaller boards versus larger boards with slightly higher performance/$ ratio, and the smaller boards won out in longterm ROI. (because they grew faster due to the fluid expansion). Especially when the larger option wouldn't be available initially for some time.

This is of course offset if the higher end board is much lower cost per MHash but I would be surprised if doing a much larger board dropped more than 10-15% off the price per chip. (just personal opinion though lol so take with a grain of salt)

Your numbers are probably in the right ballpark. Problem is, people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

[DILLIGAF]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

[Glasswalker]

Valid points

Though I doubt BFL are buying BFL because they are complete. (sure maybe some are) the majority are buying them because currently their $/MHash are the best. And their MHash/Watt are "pretty good" (especially compared to GPU).

These boards will hopefully match (maybe beat) BFL on $/MHash, and will definitely beat them on MHash/Watt.

Enterpoint does not appear to be in the "polished shiny case" product line. That's why earlier in the thread I suggested they find system integrators to partner with, who can take their boards, and resell them in nice packaged mining rigs ready to roll (to cater to that crowd).

Ultimately I don't see mounting 16 cards in a rackmount as a "hacked" solution (especially if they release a carrier board for them that powers and controls them, and allows "solo" mining for structured cluster building).

When you start talking about generic FPGA products, or a high density board that fits in a standard case, look at the Merrick 3 (24x Spartan6 LX150s on a single standard PCIe card formfactor) They already have products that serve that niche. The problem is their cost per chip actually isn't any cheaper. (without it being heavily optimized for bitcoin mining, which reduces it's usefulness for other applications)

That's why I say, even if they did build a custom FPGA board with higher density (like an ATX or EATX drop in board with say 16 FPGAs on it for mining, though look at the Merrick1, they can get a lot more than 16 chips on an ATX or EATX size board). I highly doubt we will see much more than 10% drop in cost per chip. And with that, you're still better off scaling in a fluid modular fashion (as far as long term ROI is concerned).

[DiabloD3]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

Cases double as air channels, really. The way most of these FPGAs are built are not meant for straight through airflow, which is kind of silly. Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

[DILLIGAF]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

Cases double as air channels, really. The way most of these FPGAs are built are not meant for straight through airflow, which is kind of silly. Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

Don't know why your even bother mentioning the BFL labs as a good idea then they use a similar design, I've seen more than a few my BFL is throttling posts on here.

[DiabloD3]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

Cases double as air channels, really. The way most of these FPGAs are built are not meant for straight through airflow, which is kind of silly. Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

Don't know why your even bother mentioning the BFL labs as a good idea then they use a similar design, I've seen more than a few my BFL is throttling posts on here.

I didnt mention BFL's cooling as a good idea. I mentioned their use of a SATA plug for the USB connection on their Minirigs. That actually IS a good idea. You can get enterprise SATA locking connectors that won't wiggle loose during transit.

[MrTeal]

I was planning on a setup similar to this, with two 120mm fans per pair of boards.


A couple brackets to hold the boards to the fans and duct the air down to them, and a couple sheets of plexi on the top and bottom to complete the channel. Wires through grommets in the plexi. Hopefully the fins on the heatsinks are orientated in the right direction.

Edit: The next time you guys update the website, do you think it would be possible to post a picture of the backside of the Issue 1.1 board? Thanks yohan.

[DILLIGAF]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

Cases double as air channels, really. The way most of these FPGAs are built are not meant for straight through airflow, which is kind of silly. Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

Don't know why your even bother mentioning the BFL labs as a good idea then they use a similar design, I've seen more than a few my BFL is throttling posts on here.

I didnt mention BFL's cooling as a good idea. I mentioned their use of a SATA plug for the USB connection on their Minirigs. That actually IS a good idea. You can get enterprise SATA locking connectors that won't wiggle loose during transit.

So which is it then BFL is great because it has got case or it sucks because the cooling is no good in that case. I for one am failing to see the point your trying to make here putting these boards in a case is going to lead to the same cooling problems as with the BFL.

[DiabloD3]

people want to buy BFL finished products not hack together an ugly solution.

I'm just trying to help Enterpoint produce a product that people will want. Something that drops right into a generic 1U case would be a pretty valuable product... I imagine even non-mining FPGA customers would be interested in it.

While a case maybe be nice for those that want it I have no problems with an open air solution in fact I prefer that option not only does it save me money on something I don't want/need to have my boards will run cooler due to the lack of a case. Plus could be a nice business to someone like yourself that wants case get some made and if most people are thinking like you then they can buy them from you.

Cases double as air channels, really. The way most of these FPGAs are built are not meant for straight through airflow, which is kind of silly. Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

Don't know why your even bother mentioning the BFL labs as a good idea then they use a similar design, I've seen more than a few my BFL is throttling posts on here.

I didnt mention BFL's cooling as a good idea. I mentioned their use of a SATA plug for the USB connection on their Minirigs. That actually IS a good idea. You can get enterprise SATA locking connectors that won't wiggle loose during transit.

So which is it then BFL is great because it has got case or it sucks because the cooling is no good in that case. I for one am failing to see the point your trying to make here putting these boards in a case is going to lead to the same cooling problems as with the BFL.

I don't understand your point. BFL came up with a good idea to do interconnections inside of their MiniRig. This has nothing to do with cooling. BFL does not use straight through cooling in their MiniRig either, which is a complete engineering design failure.

Putting boards in a case does not cause cooling problems as the case acts as a channel. Please do not spread FUD, and look how enterprise computers are typically designed.

[yohan]

If you were interested in say mounting in a 3U rack a bolt-on mechanical board edge could be made to make the board the right width. A wider or longer variant of Cairnsmore1 would also be possible. That's only a few minutes of design time. It's then more a manufacturing thing where it splits the volume and we buy in 2 PCBs rather than 1. However if there is a serious requirement for this and enough orders say 25+ units we could do it for a small increase in cost. Other than the PCB all the other components can stay the same and we get the volume pricing advantages of that. Worst case (small numbers) the pricing delta might be about GBP £25 / US $40 per board. If that is of serious interest to anyone it is worth contacting us. It's something we can do without a serious effect on the current batch build. The current heatsinks should work well in a rack config if suitable runner spacing is used as we considered side blow when we choose them as much as the downward standard configuration.

[DiabloD3]

If you were interested in say mounting in a 3U rack a bolt-on mechanical board edge could be made to make the board the right width. A wider or longer variant of Cairnsmore1 would also be possible. That's only a few minutes of design time. It's then more a manufacturing thing where it splits the volume and we buy in 2 PCBs rather than 1. However if there is a serious requirement for this and enough orders say 25+ units we could do it for a small increase in cost. Other than the PCB all the other components can stay the same and we get the volume pricing advantages of that. Worst case (small numbers) the pricing delta might be about GBP £25 / US $40 per board. If that is of serious interest to anyone it is worth contacting us. It's something we can do without a serious effect on the current batch build. The current heatsinks should work well in a rack config if suitable runner spacing is used as we considered side blow when we choose them as much as the downward standard configuration.

Well, I imagine a lot of people would be interested in an ATX/EATX sized board had 16 or more FPGAs that came with copper 1U heatsinks so they could drop it into cheap 1U cases. Except I think it'd require a redesign, you couldn't just fab 4 of your quad boards on one giant board and have it still fit in the ATX/EATX specs.

I'm just putting the idea out there, because there clearly is a market for things like the BFL MiniRig and I don't think the MiniRig is the right answer to the solution.

[Garr255]

If you were interested in say mounting in a 3U rack a bolt-on mechanical board edge could be made to make the board the right width. A wider or longer variant of Cairnsmore1 would also be possible. That's only a few minutes of design time. It's then more a manufacturing thing where it splits the volume and we buy in 2 PCBs rather than 1. However if there is a serious requirement for this and enough orders say 25+ units we could do it for a small increase in cost. Other than the PCB all the other components can stay the same and we get the volume pricing advantages of that. Worst case (small numbers) the pricing delta might be about GBP £25 / US $40 per board. If that is of serious interest to anyone it is worth contacting us. It's something we can do without a serious effect on the current batch build. The current heatsinks should work well in a rack config if suitable runner spacing is used as we considered side blow when we choose them as much as the downward standard configuration.

Well, I imagine a lot of people would be interested in an ATX/EATX sized board had 16 or more FPGAs that came with copper 1U heatsinks so they could drop it into cheap 1U cases. Except I think it'd require a redesign, you couldn't just fab 4 of your quad boards on one giant board and have it still fit in the ATX/EATX specs.

I'm just putting the idea out there, because there clearly is a market for things like the BFL MiniRig and I don't think the MiniRig is the right answer to the solution.

There will be a market for this, so get it made please!

[DiabloD3]

Not sure if people caught this earlier, but if a Spartan 6 maxes out at 1 amp each (assuming ~250 mhash per Spartan 6 with the most optimized bitstream possible), you could power 28 Spartan 6s off a single EPS12 plug (28 amps == 336 watts), which would really reduce the wiring mess inside of such a flat case.

I wouldn't be against someone selling a 16-24 FPGA board that fits in a 1U case (slightly custom or not) with 6 or so 10krpm 40mm fans in the front and comes with a chopped down 1U PSU inside of it that just has the EPS12 plug and no other wiring and autostarts without ATX green wire signal.

[Turbor]

Typical "fan down" heatsinks are fail, too much turbulence to be effective cooling.

Real world experience or hearsay ? You sound like an expert but do you own a board so you can prove all your theories ?