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steamboat
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May 19, 2012, 04:04:03 PM |
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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 ? i don't have time to find any published work supporting this but this is my understanding/experience concerning heatsink layout/airflow. the absolute best configuration is to create a "wind tunnel" effect using two fans in a push/pull configuration on either side of the heatsink. this creates an air channel across the fins which helps to keep air moving in a consistent direction with minimal turbulence, which increases the cooling capacity of the heatsink. it is necessary to point out that both fans need to be rated for the same cfm (or the pull fan slightly stronger) in order to avoid turbulence across the fins caused by air from the push fan getting slowed by the pull fan upon exit. second up is a fan pushing through the fins with open air on the other side. a single push configuration with a high cfm fan will generally give good airflow across the fins, with any turbulence created happening upon exiting the other side of the heatsink. this is good for open air designs where airflow inside a case does not have to be considered. the same concept works for pull configurations, though reduced efficiency may occur if air is not channeled through the heatsink, and instead pulled from around it where there is less resistance. this configuration is good for closed cases where a "wind tunnel" effect can be created and air can be directed through the heatsink by a shroud. the worst configuration is a "fan down" style mount where the fan blows air directly down on the heatsink. this causes an "air cushion" to form at the base of the heatsink which creates a bubble of turbulent air causing resistance, which reduces the amount of air actually flowing across the fins. also, fan down configurations are often open air, which further reduces efficiency by allowing air to bypass the heatsink completely by flowing around the edges. tl;dr. he's right, it's cooling 101. |
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"Bitcoin: the cutting edge of begging technology." -- Giraffe.BTC
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seriouscoin
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May 19, 2012, 05:01:10 PM |
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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 ? hearsay? lol If you take that as some sort of "expert" knowledge, i wonder what your "common sense" is |
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yohan (OP)
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May 19, 2012, 05:34:59 PM |
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 Issue 1.1 board no2. showing heatsink for first 100 units after then the same style but 10mm shorter. We will sell the longer version as an option probably in a copper option. |
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Garr255
Legendary
 Offline
Activity: 938
Merit: 1000
What's a GPU?
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May 19, 2012, 05:41:25 PM |
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“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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Turbor
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BitMinter
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May 19, 2012, 06:05:47 PM |
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If you take that as some sort of "expert" knowledge, i wonder what your "common sense" is
Ever heard about "sarcasm" ? Let me get it strait. I spent quite some time with my quad and my single boards to find out the best way to cool them. It doesn't really matter if you blow them with a tiny 40mm fan direct on the heatsink or with one or two 120mm fans from above or from the side. It also depends on the heatsink. The "gain" between a 120mm and a well placed 40mm is ridiculous. But I wish everyone that wants to build the perfect case good luck  @yohan looks great |
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yohan (OP)
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May 19, 2012, 06:37:08 PM |
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 The designer is watching. |
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Glasswalker
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May 19, 2012, 09:53:46 PM |
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The designer is watching. LMAO! That was unexpected and awesome  Bitcoin-kitteh is on the prowl! |
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antirack
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May 20, 2012, 04:34:48 AM |
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Let me get it strait. I spent quite some time with my quad and my single boards to find out the best way to cool them. It doesn't really matter if you blow them with a tiny 40mm fan direct on the heatsink or with one or two 120mm fans from above or from the side. It also depends on the heatsink. The "gain" between a 120mm and a well placed 40mm is ridiculous. But I wish everyone that wants to build the perfect case good luck How many FPGAs do you have? |
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Garr255
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What's a GPU?
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May 20, 2012, 07:19:18 AM |
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I have raised a motion to expand cognitive using five of these boards! https://bitcointalk.org/index.php?topic=67547.msg910317#msg910317 |
“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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Keninishna
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May 20, 2012, 07:29:31 AM |
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 This is really what hes thinkin. |
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Turbor
Legendary
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BitMinter
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May 20, 2012, 08:02:47 AM |
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Let me get it strait. I spent quite some time with my quad and my single boards to find out the best way to cool them. It doesn't really matter if you blow them with a tiny 40mm fan direct on the heatsink or with one or two 120mm fans from above or from the side. It also depends on the heatsink. The "gain" between a 120mm and a well placed 40mm is ridiculous. But I wish everyone that wants to build the perfect case good luck How many FPGAs do you have? Never enough  only small numbers of different boards. So no big cluster to box in. |
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this time
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May 20, 2012, 09:51:11 PM |
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What are the dimensions of the barrel power jack? Same as BFL?
Inner diameter: 2.5mm
Outer diameter: 5.5mm
Barrel length: 12mm
Polarity: Center 12V
thanks
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wildemagic
Member
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Merit: 10
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May 20, 2012, 10:26:40 PM
Last edit: May 20, 2012, 10:45:20 PM by wildemagic |
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Yohan, it looks like you have the provisions for a molex power and fan headers, will these be on the boards, or just as in the picture?
Just re-read your updated first post, answered my own question <grins>
kind regards
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.,-._|\ Offgrid 1.7kW Solar and 3G wireless internet powering my mining rig.
/ .Oz. \
\_,--.x/ [219.5btc of successful trades total] with : rastapool, miernik, flatronw & OneFixt
o
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TheHarbinger
Sr. Member
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Activity: 378
Merit: 250
Why is it so damn hot in here?
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May 21, 2012, 12:19:25 AM |
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Yohan, are you guys working on accepting bitcoins for payment directly, or through BitPay perhaps? I would prefer not to have to go through the whole "sell at an exchange, transfer to bank (5 days), withdraw funds, load to a prepaid card" hoop-jumping-through procedure if at all possible.
I'm quite sure most of us that have pre-ordered are funding the purchase with BTC in some way or another.
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12Um6jfDE7q6crm1s6tSksMvda8s1hZ3Vj
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Garr255
Legendary
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Activity: 938
Merit: 1000
What's a GPU?
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May 21, 2012, 12:25:32 AM |
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Yohan, are you guys working on accepting bitcoins for payment directly, or through BitPay perhaps? I would prefer not to have to go through the whole "sell at an exchange, transfer to bank (5 days), withdraw funds, load to a prepaid card" hoop-jumping-through procedure if at all possible.
I'm quite sure most of us that have pre-ordered are funding the purchase with BTC in some way or another.
+100 Accept BitPay at the very least. |
“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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TheHarbinger
Sr. Member
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Activity: 378
Merit: 250
Why is it so damn hot in here?
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May 21, 2012, 12:39:07 AM |
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Yohan, are you guys working on accepting bitcoins for payment directly, or through BitPay perhaps? I would prefer not to have to go through the whole "sell at an exchange, transfer to bank (5 days), withdraw funds, load to a prepaid card" hoop-jumping-through procedure if at all possible.
I'm quite sure most of us that have pre-ordered are funding the purchase with BTC in some way or another.
+100 Accept BitPay at the very least. No, I think the very least would be Mt.Gox codes. The very best would be direct BTC. BitPay would be damn good. |
12Um6jfDE7q6crm1s6tSksMvda8s1hZ3Vj
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cyberlync
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May 21, 2012, 12:58:32 AM |
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Yohan, are you guys working on accepting bitcoins for payment directly, or through BitPay perhaps? I would prefer not to have to go through the whole "sell at an exchange, transfer to bank (5 days), withdraw funds, load to a prepaid card" hoop-jumping-through procedure if at all possible.
I'm quite sure most of us that have pre-ordered are funding the purchase with BTC in some way or another.
+100 Accept BitPay at the very least. +1 |
Giving away your BTC's? Send 'em here: 1F7XgercyaXeDHiuq31YzrVK5YAhbDkJhf
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yohan (OP)
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May 21, 2012, 07:30:05 AM |
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At the moment we are not taking Bitcoins or margin is too slim to consider anything that we don't fully understand all aspects of and right at the moment we are too busy to do that work. The volatility of exchange rates is also an issue for things being delivered up to 1-2 months. All of our costs are GBP or USD and we have no other option to reduce exchange risk and to use those currencies. Even the euro is becoming a problem although we already margined that. Our margin there is gone in the last week or so and we are watching what happens there. All of these traditional currencies have a big momentum and rarely change quickly which cannot be said about Bicoin.
MtGOX haas been suggested but elsewhere in the forum there are reports of problems and possibly insolvency so that is a big problem for us to go that way until it is clear what is the real situation.
Yohan
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MXRider
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May 21, 2012, 07:45:54 AM |
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Are you going to test hashing soon?
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gr0bi42
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May 21, 2012, 08:29:14 AM |
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Issue 1.1 board no2. showing heatsink for first 100 units after then the same style but 10mm shorter. We will sell the longer version as an option probably in a copper option. Hi Yohan, I like the heatsinks you're using. Especially in copper. I'm looking around quite a while for a good and cheap heastsink. Not that easy... I've found the Oetzi Alpenfoehn, but it's huge and expensive. The Enzotech heatsinks are better and very similar to yours, but even more expensive and always out of stock. What heatsink you are using? Where can I buy it? |
Donations are welcome: 1Btf3BqUegfe5iFdWsgfBf1Ew3YsAvsrLT
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