Be careful with that.  I've heard stories where ppl had that kind of configuration, and somehow turned one PS off while the other was still on.

The PS that was in the off state decided to short the +12V rail to ground, and Bad Things happened.  The magic smoke got let out of some wires and traces and other things.

Well yes -- I do know about the search box....

But as for wanting to read 27 pages to direct someone to a post that is not composed mostly of predigested cattle feed is a chore in itself... Then as the firmware advances and things change material becomes out of date -- like the current power/current draw on the units.

I have followed this thread on and off since the first post -- followed the moaning and the threats.... some entertaining -- most not worth the electrons used to compose the posts. Unfortunately there is useful information that is worth gleaning -- but it's like picking fly dung out of pepper.

Almost every discussion topic in the thread has been polluted with junk -- some well meaning -- too much just pointless.

Anyway -- maybe people can clean up their act and stick to useful stuff -- but I won't bet the farm on it.

When the diff had go to 510

At 6 of November 2013 or at 5 November 2013

i'm sorry to correct you, but the initial firmware(0.90) was 890-910W--- 0.9V @ ~60A per VRM

The only forum I am part of that can get hateful over PSU selection.  Kind of addicting, you just have to watch the carnage...

Nope.  Power supplies are rated on output.  At most efficiency would be 90% on the high end of the load curve.  So 900W AC *0.90 = 810W.
Overspec (>850W DC) would be > 944W AC observed (850/0.90 = 944W AC).

If the power supply was less efficient that would mean the DC load was actually LOWER.  (i.e. 900W AC observed on a 85% efficient PSU would be only 900W AC * 0.85 = 765W.

Does anyone know if orders placed today will be delivered by month end?

Cheers

That's what all of us with orders are all hoping for.

By rights they ought to be, as it specifies "November shipping" right on the product page.

Of course it's possible for them to ship in November, but not be delivered until December.  Especially if you don't select the express shipping option.  (does anyone actually not select express shipping?)

Um, yep....why do you think those PSU's were shutting off?  And your "spec calculation" is over simplistic, btw...just because a PSU is rated for an overall wattage doesn't mean that an individual rail is.  In some cases, the total +12V wattage is less than the overall PSU wattage rating because they were coming in just under the wire, so to speak, to meet a "common" PSU rating cut-off and the lower voltages are necessary to add in to reach the overall number.  For instance, the Corsair HX850 that was the center of the controversy is an 850-rated PSU but only rated a maximum of 840W +12V with apparently little to no safety margin built-in given the observed results.
http://www.corsair.com/en/media/cms/manual/corsair-psu-spec-table-091813.pdf

As for the "at best efficiency"...well, at near 100% load you aren't going to get that, now are you?  Again, according to manufacturer's specs you could expect 87.73% @115V input.  So put the lower actual rated rail wattage coupled even with lower real-world efficiency when running with a wall power reading of over 970W (and yes, those levels were typical prior to version .95 of the firmware for jupiters) and guess what?  You are running that thing over-spec at time of KnC initial release and that's why those things were shutting themselves off and then coming back with a bang in some cases upon recovery.


Others PSU models/brands are actually under-rated in that the combination of the +12V rails actually oversubscribes the overall rating, and the rating itself has a safety margin built-in to it so that the PSU is rated (according to manufacturer documentation) to be able to deliver over the rating (which would be the one you would probably want to buy).

And yes, once again, machines with fully functional chips with initial firmware could very much pull that much wattage..hence the issue.  With .94 firmware mine would peak at 945W long-term sustained at the wall according to my UPS readout with higher spikes depending on what cores were enabled/disabled at the time.  I never ran .90 but I know that rev pulled at least as much. Was I the only one paying attention when all that was going down?  When you actually have one to play with, try putting a pre-.95 firmware on it and let us know how much power you see it pull, k? 

edit:  clarified verbiage to better express thought chain.

Simplistic or not it was accurate.  Most modern PSU provide 90% to 100% on the 12VDC rail because they do conversion of all AC power to 12VDC and then power the other rails off the 12V rail.  

Sorry typo ment to say at worst efficiency was .....  Still if the efficiency was WORSE than 90%, say 88% then that only reduces the relative DC load as it compares to the observed AC load.  850W/0.88 = 956W.  850W/0.85 = 1000W.  You telling me people have reported >950W at the wall?
Nonsense.

So once again 850W is fine.  A single person reported a single problem with a single model of a single brand of power supply and you want to say 850W is insufficient as a blanket statement.  Strange KNC's entire datacenter is powered by nothing but 850W PSUs.  KNC still recommend 850W on the site.  Many people are using 850W PSUs today without issue.  The idea that one needs 1250W or 1600W to power a 600W DC load is well just silly.


Math isn't your strong suit is it?   840W 0.8773 = 957W.   The LOWER THE EFFICIENCY the higher the observed AC load compared to the actual DC load and power supplies are rated by their OUTPUT not INPUT.  So you are actively disproving your point.  Now if the unit was 99.9% efficient then yes >850W at the wall would indicate the unit was running beyond peak load.  I used 90% because most 80-Plus PSU are within a few % of 90% and certainly don't go much above it on the high end.  Still we can use the lower 87.7% that only means the DC load was EVEN LOWER!