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-   -   I call her "Prime Box" (https://www.mersenneforum.org/showthread.php?t=21225)

Fred 2016-04-18 18:44

I call her "Prime Box"
 
32 cores of prime hunting goodness

[url]https://drive.google.com/folderview?id=0B4ih9VD3mGSrTFpiV3FuQU1Bakk&usp=sharing[/url]

Mark Rose 2016-04-18 18:58

Tempting...

bgbeuning 2016-04-18 21:33

She is very pretty.

You used ATX-24 power splitters instead of the PicoPSU's.
So does pressing the power switch on any board start the PSU for all of them?

Prime95 2016-04-18 22:53

[QUOTE=Fred;431885]32 cores of prime hunting goodness[/QUOTE]

Very nice, I'm jealous. I just started ordering parts for CPU #6 and #7. I guess I need to cram in CPU #8 or I'll feel inferior. :smile:

BTW, where did you get the Y-cables? Temps OK? From what I can see only the PSU fan is moving air through the enclosure?

Fred 2016-04-19 00:37

[QUOTE=bgbeuning;431904]She is very pretty.

You used ATX-24 power splitters instead of the PicoPSU's.
So does pressing the power switch on any board start the PSU for all of them?[/QUOTE]


Ebay: [url]http://www.ebay.com/itm/261180756961[/url]

No power switches. I used a paperclip across the power button connector on the motherboard to power them up initially, and then set the bios of each motherboard to auto power on upon power restore. If I lose power, they would all just power up upon power being restored. If I want to power cycle one or all of them for any reason, I just power down (via the OS) all 4 motherboards on any given power supply. Then to restart I just flip the power switch on the power supply (which simulates power loss), and all 4 start back up.

Fred 2016-04-19 00:47

[QUOTE=Prime95;431909]Temps OK? From what I can see only the PSU fan is moving air through the enclosure?[/QUOTE]

Temps are good. In the upper 70s, but it's warm in my office today. There is no powered ventilation, but the entire back (that you can't see in the pics) is wide open. Also, there are large 3 inch or so gaps between the sheets of acrylic (front center and the corners). The acrylic is really just to give the "box" extra rigidity. With all the gaps and the back wide open, I don't think temps will be an issue.

Wednesday the whole thing heads in to the college I work at. One of my buddies in IT is letting me stick it in one of his network closets. Might as well let the college burn the 600 watts. It [B]IS[/B] math research after all.

Besides, that will clear space on my desk at home to start Prime Box 2. :wink:

Mark Rose 2016-04-19 00:56

[QUOTE=Fred;431913]Ebay: [url]http://www.ebay.com/itm/261180756961[/url][/QUOTE]

That's a lot cheaper than the George's solution. I did not know that the CX430M could supply enough power off the ATX-24 cable for four boards!

Fred 2016-04-19 01:29

[QUOTE=Mark Rose;431915]I did not know that the CX430M could supply enough power off the ATX-24 cable for four boards![/QUOTE]

It was perhaps a bit naive of me. I'm not really that into hardware. Seemed like it should work so I gave it a go. Each side (of 4 boards) draws about 300 watts at the wall and they seems to be running fine. I've had the first stack of 4 running for at least a couple months now without issue.

Prime95 2016-04-19 04:05

[QUOTE=Mark Rose;431915]That's a lot cheaper than the George's solution. I did not know that the CX430M could supply enough power off the ATX-24 cable for four boards![/QUOTE]

Indeed, much cheaper. I was trying to distribute the power over multiple PSU cables. I might now try a mixture -- power 3 or 4 boards with splitters and 3 or 4 with picoPSUs.

Madpoo 2016-04-19 16:13

[QUOTE=Fred;431914]Wednesday the whole thing heads in to the college I work at. One of my buddies in IT is letting me stick it in one of his network closets...[/QUOTE]

And hopefully it's cooled in there too... extra bonus.

bgbeuning 2016-04-20 12:32

[QUOTE=Fred;431913]Ebay: [url]http://www.ebay.com/itm/261180756961[/url]

[/QUOTE]

Those use 18 gauge wire which I would recommend limiting to under 10 A current.
(Wikipedia says 14 A heats AWG 18 wire to 90 C.)
300 W at 12 V is 25 A so the PSU wire needs AWG 12 or 14.
And it would be having 12.5 A on the first Y cable.
The above is the worst case. The load is probably spread over multiple wires.

If none of the wires feel hot to the touch, it should be safe.
A "loop" current meter will let you check each wire.


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