DiabloD3
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Activity: 1162
Merit: 1000
DiabloMiner author
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May 11, 2012, 08:19:35 PM |
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... Again, I just said you can get a 0.5C/W or lower heatsink if you go large or loud enough.... But no one wants to do that  The whole idea about FPGAs is that they are smaller, cooler, less noiser than GPUs. Even if you achieve 2.7C/W top power draw shouldn't be more than 17W, commercial grade chips, 25W industrial grade chips at 25C ambient temp. Compared to 40W of one chip in BFL Single is damn small value. And we have to remember that propagation delays thru silicon raises when temperature raise. More power draw, faster MHz limit = less MH/s. There is somwhere a sweet spot and it's defenitevely below 17W thanks to high Rthjc... Are we agreed? Yes, definitely. I wouldn't want to get nearly that close to the limit. That being said, if someone like eldentyrell releases a bitstream that does 250MH/s on an LX150 but pushes power consumption up to 15W, there are options out there that might be worthwhile to deal with that.  Thats up from 200 mhash, right? I wonder how many of these boards should have been equipped with big copper heatsinks instead. |
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rjk
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Activity: 448
Merit: 250
1ngldh
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May 11, 2012, 09:08:43 PM |
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... Again, I just said you can get a 0.5C/W or lower heatsink if you go large or loud enough.... But no one wants to do that The whole idea about FPGAs is that they are smaller, cooler, less noiser than GPUs. Even if you achieve 2.7C/W top power draw shouldn't be more than 17W, commercial grade chips, 25W industrial grade chips at 25C ambient temp. Compared to 40W of one chip in BFL Single is damn small value. And we have to remember that propagation delays thru silicon raises when temperature raise. More power draw, faster MHz limit = less MH/s. There is somwhere a sweet spot and it's defenitevely below 17W thanks to high Rthjc... Are we agreed? Yes, definitely. I wouldn't want to get nearly that close to the limit. That being said, if someone like eldentyrell releases a bitstream that does 250MH/s on an LX150 but pushes power consumption up to 15W, there are options out there that might be worthwhile to deal with that. Thats up from 200 mhash, right? I wonder how many of these boards should have been equipped with big copper heatsinks instead. Watercool that shit. |
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ice_chill
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May 11, 2012, 09:36:22 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
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MrTeal
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Activity: 1274
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May 11, 2012, 09:39:38 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
If a fan is pushing air across it, how is it passive? |
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TheHarbinger
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Activity: 378
Merit: 250
Why is it so damn hot in here?
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May 11, 2012, 09:44:34 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
Yes, they are serious. But not as serious as me. Four Peltiers, then the heatsinks, then the watercoolers, all submerged in mineral oil, sealed into a 55 gallon metal drum, sunk down into Challenger Deep. I figure I can get about a half a TH/s from each core. |
12Um6jfDE7q6crm1s6tSksMvda8s1hZ3Vj
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ice_chill
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May 11, 2012, 09:51:17 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
If a fan is pushing air across it, how is it passive? I meant a case fan in the enclosure, but not a fan on the heatsink, a bit like we get passive PC video card, but still need a casefan to have the air moving.  |
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MrTeal
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Activity: 1274
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May 11, 2012, 09:53:08 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
If a fan is pushing air across it, how is it passive? I meant a case fan in the enclosure, but not a fan on the heatsink, a bit like we get passive PC video card, but still need a casefan to have the air moving. That's not passive then if you're relying on a fan to move air. Convection should be enough. |
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Gomeler
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May 11, 2012, 09:54:51 PM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
I'm seriously considering watercooling these. It depends on if a faster bitstream is released that could be thermally limited by the small heatsinks we're using on these FPGAs. If I can get another 15-30% by watercooling and keeping the core temps low then I'm all for it. |
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Glasswalker
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May 12, 2012, 12:25:15 AM |
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lol are you guys serious water cool 15watts ? and the chip runs at 1.2v ? A passive heatsink with 120mm fan pushing air across will be enough.
While generally yes a heat sink and fan will do fine. The reason alternatives are being considered with such a low wattage is because the FPGA package has such a poor thermal conductivity. It is a plastic chip package not a nice metal heat spreader like on gpu/CPU. So the chip core will always be quite a bit warmer than the package surface. Especially at higher power dissipation. High heat can also impact performance and bit coin mining is already pushing these chips much harder than most other Applications do. Anyway either way yes a normal heat sink with a fan or very good case airflow should be fine. Send from my android phone. Please excuse typos and brevity. |
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Turbor
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Activity: 1022
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BitMinter
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May 13, 2012, 11:15:12 AM |
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Yohan, what will be the price for the quad for non preorders ? |
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pieppiep
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May 13, 2012, 11:23:31 AM |
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Yohan, what will be the price for the quad for non preorders ? In the opening post : "After we complete the benchmarking/software work the price will increase by 50% to cover our costs in doing this work and general support." So £600/$960/780€ |
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Turbor
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Merit: 1000
BitMinter
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May 13, 2012, 12:06:51 PM |
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Yohan, what will be the price for the quad for non preorders ? In the opening post : "After we complete the benchmarking/software work the price will increase by 50% to cover our costs in doing this work and general support." So £600/$960/780€ Thanks |
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yohan (OP)
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May 13, 2012, 02:36:41 PM |
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Currently quad is still at the offer price of GBP £400/ US $640 / 520€. Delivery is currently quoted at July but July capacity is going rapidly.
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yohan (OP)
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May 15, 2012, 06:02:11 AM |
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Schedule update
We are maintaining our schedule for production and whilst we can never rule out a problem occuring that changes this schedule, e.g. like a PCB manufacture issue, we should ship between 20-50 units in May. We will be asking payment from some of you next week.
The first week of June should see more of you get units.
The second week of June there will be few shipments partly because we are waiting for heatsinks but also the major public holidays that are in the first week of June will limit assembly output from that week which forms basis of shipment in the second week.
Week3 of June will see shipping pickup substantially once next batch of heatisnks arrive.
Yohan
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Garr255
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What's a GPU?
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May 15, 2012, 06:09:03 AM |
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PM sent on behalf of Cognitive. |
“First they ignore you, then they laugh at you, then they fight you, then you win.” -- Mahatma Gandhi
Average time between signing on to bitcointalk: Two weeks. Please don't expect responses any faster than that!
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allinvain
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Activity: 3080
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May 15, 2012, 09:17:51 AM |
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Or MPBM Since MPBM already has good Icarus support I'd imagine this board should work pretty much the same if you use the Icarus bitstream. |
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Bitinvestor
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May 15, 2012, 11:54:05 AM |
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Those who cause problems for others also cause problems for themselves.
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yohan (OP)
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May 15, 2012, 03:37:51 PM |
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We will be looking at this side over the next few weeks to determine who to talk to and what to do.
Do remember we are still going through a very big learning process and the hardware is only now coming in decent numbers. The hardware design and manufacturing side is something we are very good at but don't confuse that with it being simple. It takes an awful lot of people time and others resources to run such a large, rapid volume ramp, build like we are doing with Cairnsmore1 and keep it on schedule.
Yohan
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