[Review] Spondoolies SP20 review - A Green miner with a Loud fan

[Syke]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

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[johnyj]

Everyone that done review have hashrate dip to 0 in 1day hashspeed chart. In your case was the same? This units resets itself in 1 day periods?

I have done two session (some modification and tweaking in between), the latest one is 20 hours but have not experienced any drop in performance

[Guy Corem]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

Every system has tradeoffs. In the SP3x series as well, the cooling solution isn't symmetric.

In case of the SP10, with the shared heatsink, the cooling was more symmetric.

The RockerBox ASICa with the FCBGA package aren't suitable for shared economocial heatsink. Mechanical stress, etc.

The system may be tweaked for better results. The entire software is open source as well.

Disclaimer: Modifying will cause a warranty lost.

[johnyj]

A high-end solution would be vapor chamber based heat sink, but it is really a pain to recondition all of the 8 chips even if you have the new heat sink with the right size/mounting. I have not find a good way to remove those hardened glue without risking hurt the die under the heat sink. I will just leave the original heat sinks as they are



The difficulty trend is down, it is worth to do some tweaking when operating life expectancy is increasing

[johnyj]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

Maybe you can do some air channel to send some cold air into the back row of the heat sink

I just checked the ASIC stats page,  on my underclocked unit at 0.6V, the difference between different ASIC chips is maximum 10 degrees

[Syke]

I just checked the ASIC stats page,  on my underclocked unit at 0.6V, the difference between different ASIC chips is maximum 10 degrees

Yeah, they're great when underclocked.

[johnyj]

Success! Lowered noise to 60 db! Now it is not audible anymore when the door is closed. It is a comfortable level even when I'm sitting beside the rig, just feels like in a server hall, not industry warehouse with lots of machinery. The room's ambient noise is 33 db before running SP20

After 15 minutes of running, with a front temp of 25c degree, I get 60c degree for back temp, and none of the ASICs reached minimal  watching threshold of 85c degree

The test method learned from Biffa:


The fan speed regulator is running at 5V, but with such a large load, it gets very hot. I hang it up at the exhaust to cool it, but will try to make the adapter to utilize the PWM socket on board later


Hero of the day: Delta AFC1212DE.

This fan consumes 3A at its maximum output, so should be as powerful as the stock fan. However, it has 7 blades instead of 5 on the stock fan, so the noise performance is much better. In principle any 7-blades 120x38mm delta fan could dramatically reduce the noise

[johnyj]

Record! Noise down to 48 db. Now even without door closed, I can barely hear it 10 meters away. Accomplished by previous low speed fan king GT1850

At ambient temperature of 14c, it can keep the back end temp at 60c. But now the difference between the lowest temp DC module and highest temp DC module is as high as 30 degree (33/66), the air flow is not fast enough to cool the second ASIC module in the channel.

At 22c degree ambient, back end reached 68c, now two of the ASICs reached 105c. It seems with this weaker fan, even at 0.6v you can not run at an ambient temp over 25c degree

So delta fan is still the better choice

Another issue: The metal ASIC board stopper under the fan is so high that it has a direct contact with the fan, that's the reason adding rubber pin for the fan did not remove the vibration noise from the case. I removed that stopper totally and the vibration noise is gone (When fully assembled, ASIC boards are fixed by other screws, even without this stopper they won't move)

[mavericklm]

This fan consumes 3A at its maximum output, so should be as powerful as the stock fan. However, it has 7 blades instead of 5 on the stock fan, so the noise performance is much better. In principle any 7-blades 120x38mm delta fan could dramatically reduce the noise

Noted!

Very nice drop in decibels!

[johnyj]

This fan consumes 3A at its maximum output, so should be as powerful as the stock fan. However, it has 7 blades instead of 5 on the stock fan, so the noise performance is much better. In principle any 7-blades 120x38mm delta fan could dramatically reduce the noise

Noted!

Very nice drop in decibels!

I just tested with stopper moved out of the box, even without the vibration noise, stock fan at 20% speed still generate 68 db, maybe because of the lowest operating voltage for stock fan is 7 volt. But its cooling effect is strong, even at 27c at frond end, the back end temp never goes above 50c

And with GT1850, after a while I opened the case, some part of the case is extremely hot, especially the last ASIC heatsink, definitely over 100c, dangerous

[klondike_bar]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

why is your intake temperature so high? thats the problem. Ideal intake is about 15-30C and ideal outlet is 65-75C

[johnyj]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

I agree with you, after 3 days of testing, I found out that those 4 ASICs in the back row are much more stressed due to the uneven cooling design of the case, and since the front row of heatsinks totally block the air passage to the back row, there is no easy way to get cold air into the back row without passing through the front row heatsinks, especially the second heatsink near the bottom of the case, since the heat air from the first heatsink has nowhere to go but pass the second heatsink

Some kind of cold air intake duct can be constructed, but that will be very time consuming, maybe only suitable for one or two units

[philipma1957]

The second set of chips get hit with warmer air, but not +40C hotter.

Ok, my intake is about 40c, and exhaust is about 80c, so the back chips are getting +20c air. It significant enough that they are downclocked 200 MHz as a result of the hot air from the front chips.

I agree with you, after 3 days of testing, I found out that those 4 ASICs in the back row are much more stressed due to the uneven cooling design of the case, and since the front row of heatsinks totally block the air passage to the back row, there is no easy way to get cold air into the back row without passing through the front row heatsinks, especially the second heatsink near the bottom of the case, since the heat air from the first heatsink has nowhere to go but pass the second heatsink

Some kind of cold air intake duct can be constructed, but that will be very time consuming, maybe only suitable for one or two units

or set watts lower for them and set starting volts lower for them.

 I am running 5 stacked and 1 on a shelf.


I had  2 ways of heat+noise management.  heavy down clock to 1150-1200gh fans at 20-30%  since they are in an attached garage noise is not a big deal and I can even close the back door of the garage

   or a higher clock at 1300-1350 fans at  50-60% and  stagger the settings.  I have to open the back  door  of the garage for at least 3 hours each day.  and they are a little too loud.   

bottom line 7200gh vs 8100gh.   3900 watts  vs 4775   .54 watts a gh vs  .59 watts a gh 

 and a happy wife  which is very valuable in life indeed.

I have decided to go with the lower clockings for now.

[johnyj]

Made an aluminum block to narrow down the lower channel





Unfortunately the result is worse, temps rose by a couple of degree under same ambient temp, maybe some turbulence made fan spin slower

[raskul]

excellent review and some great tinkering. well done on getting such low w/gh

[johnyj]

I added some aluminum guides in the heat sink so that the warm air from the first heatsink does not go straight onto the second, but the effect is minimum

Then I noticed that there are 2 large holes before the last 2 ASICs, perfectly suitable for a test of cold air intake modification. I used some plastic foil to wrap the rest of the case, leave these 2 holes open widely by flipping the controller board to the other side



This immediately lowered the temp of the hottest ASICs. As a result, the hash rate jumped: The system's frequency management look at the highest temp ASIC to adjust the frequency of the other chips. Now the back row ASICs can be cooled more, the rest of the chips were tuned up accordingly. And you can see now all the temps are getting close (chip nr.4 is possibly faulty)



It is also worth noting that the front temp on SP20's statistic page is not the ambient temp (I mistakenly thought so in previous posts), it is affected by the airflow speed. With original setup, the front temp reads 18c when ambient temp is 14c (measured by a thermometer in front of the main air intake of the SP20). And in my modified setup, the from temp reads 25c

[wh00per]

It is also worth noting that the front temp on SP20's statistic page is not the ambient temp (I mistakenly thought so in previous posts), it is affected by the airflow speed. With original setup, the front temp reads 18c when ambient temp is 14c (measured by a thermometer in front of the main air intake of the SP20). And in my modified setup, the from temp reads 25c

nice catch !

[johnyj]

Aluminum sheet guide installed on the heatsink. Since the system adjust the frequency depends on ASIC's temp, which is not visible in the ASIC stats page (only visible once it is above 85 degree), I don't know if this modification works. However, without this modification, the system runs at 5% lower frequency, so I suppose it has some effect

[johnyj]

When I install those guides, I found out that one of the heatsink does not have those two drops of glue on its side, thus it can be easily tilt or shake by hands. I removed it, cleaned thermal grease, it turns out all of the chip's corner are broken. Without those 2 drops of glue, I can imagine it get knocked by each vibration during transportation



This is a weakness of the cooling system. Like Spondoolies-Tech pointed out, The RockerBox ASICs with the FCBGA package aren't suitable for mechanical stress, since its die directly exposed, and it is small: only 10x11.5mm in size.

The problem is, the heat sink is just too big for the small contact surface of the die, and it has only 2 point of tension. To make things worse, its tension is flexible because of the spring in each screw, this means it will just tilt to any direction and break the corner of the die with the least amount of incaution during install/transportation. So that's why they end up using some glue to permanently fix the heatsink on the board

And, to my surprise, the copper plate is just attached together with the aluminum heatsink with thermal compound without any screw.
They can slide against each other. This means most of the heat will be transferred to the heatsink by this layer of thermal compound, which has magnitudes lower thermal conductivity than either aluminum or copper. When installed, the pressure between them is decided by the spring of those 2 screws, and it is very weak (otherwise it will break the die)

[mavericklm]

Sexy!

The chipped corners reminds me of amd xp, durons... nice times!

It would be nice to have a miner with lga775(or newer) socket mounting holes! then i can be motivated to repair my cascade system for -80c cooling