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Author Topic: Swedish ASIC miner company kncminer.com  (Read 3012586 times)
davewr2013
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November 11, 2013, 02:27:51 AM
 #20601

Jebus we've had this PSU discussion at least twice before. Just buy the PSU that you want that has at least the minimum spec the manufactrer recommends. Personally I run mine off a 1500W Silverstone connected to a 2200W UPS. But that's what I just had lying around after my CM 850V died.

A lot of people still come to the thread and start at the end...

Reading 100+ pages of mostly drivel would try the patience of a saint. Shocked


LOL

There is also a search box, pop PSU in there while in the thread and its amazing what comes back.

Of course its no issue people not wanting to read the thread, but then it goes on and on rehashing the same old arguments and the thread gets full of crap.

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 Then as the firmware advances and things change material becomes out of date -- like the current power/current draw on the units.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. Roll Eyes

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


Give me this day my daily Bitcoin...
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davewr2013
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November 11, 2013, 02:31:20 AM
 #20602

700W AC is 630W DC.  Power supplies are rating on DC load.  630W load on 850W supply is <80%.

Maybe you could take us unenlightened souls through how you come up with these numbers. Perhaps even, you could point out whether Power Factor comes into play in this calculation.

Just askin'

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November 11, 2013, 02:31:40 AM
 #20603

When the diff had go to 510

At 6 of November 2013 or at 5 November 2013
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November 11, 2013, 02:41:28 AM
 #20604

700W AC is 630W DC.  Power supplies are rating on DC load.  630W load on 850W supply is <80%.

Maybe you could take us unenlightened souls through how you come up with these numbers. Perhaps even you could point out whether Power Factor comes into play in this calculation.

Just askin'

Well measured AC Wattage will already take into account power factor.  If someone is measuring Volts and Amps it needs to be adjusted for the PF but the PF of modern switching supplies is generally pretty good (0.99).

The difference between AC Wattage and DC Wattage is simply the efficiency of the unit and for modern 80-Plus Gold PSU 90% is a good estimate (of course if you know the exact model you can look up the curve).

So 630W DC load will draw 630/0.9 = 700W AC.
The power supply converts 700W of AC electrical energy into 630W of DC electrical energy and 70W of thermal energy (heat.

Simple version is power supplies are rated by their output.  The output is always going to be lower than the input as no power supply is 100% efficient.
Output = Efficiency * Input
Input = Output / Efficiency
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November 11, 2013, 02:46:36 AM
 #20605


For a KNC Jupiter it could well end up drawing 750 Watts (perhaps a bit more) -- I would recommend a 1000 Watt supply as the minimum.

It would be better with a 1200 Watt capable supply. (Safety margin)

Most engineers like lots of safety margin. In this case the extra cost is cheap insurance.

You think KNC engineers have made the wrong recommendations with 850W PSU?


KNC makes this recommendation:
What specs do I need for the powersupply?
- A power supply (PSU) certified as 80+ Gold (high quality power with low variations).
- for Jupiter models, an 850 Watt PSU with a minimum of four separate PCI-E adaptors (6 pins or 6+2 pin).
- for Saturn models,a 600 Watt PSU with a minimum of two separate PCI-E adaptors (6 pins or 6+2 pins).
- for Mercury models, a 400 Watt PSU with a minimum of one PCI-E adaptor (6 pins or 6+2 pins).


However, as some pointed out the new firmware is causing some units to draw more current (power).

You pays your money -- you takes your choice.

It's your money sunk into those miners -- not mine.

I think that some have pointed out their Saturns are running close to 360-380 Watts -- a Jupiter has two more towers.

Some of us own voltmeters and know how to use them -- so our opinions may be biased by the readings. Wink

Cheers!



Yes but the initial firmware was drawing around 550 watts at the wall, so you have an entire 300 watts grace. I've also seen those 850s comfortably pull 1000W recently, though I doubt they do so long term! Wink

i'm sorry to correct you, but the initial firmware(0.90) was 890-910W--- 0.9V @ ~60A per VRM
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November 11, 2013, 02:50:55 AM
 #20606



i'm sorry to correct you, but the initial firmware(0.90) was 890-910W

Exactly, which meant that 850W PSU's were put into an over-spec situation, and some of them handled it badly (eg the Corsair psu's that came back from the safety-shutdown mode and popped capacitors on the hashing boards).  Firmware all the way to .94 was pulling 900+ at the wall.

So in answer to CYPER's question...hell yes, it was a bad recommendation.  I'm glad I got a 1000W which accounted for KnC's screw-up in power estimation.  Granted, later firmware has rendered the issue moot..but for the initial release it was a swing-and-a-miss by KnC on that 850W recommendation for sure.
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November 11, 2013, 02:55:36 AM
 #20607

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

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November 11, 2013, 03:00:00 AM
 #20608

So in answer to CYPER's question...hell yes, it was a bad recommendation.  I'm glad I got a 1000W which accounted for KnC's screw-up in power estimation.  Granted, later firmware has rendered the issue moot..but for the initial release it was a swing-and-a-miss by KnC on that 850W recommendation for sure.

900W AC power is within spec of V850 Wink

Even 950W AC will be within spec on 240V Wink

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Gerald Davis


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November 11, 2013, 03:03:21 AM
 #20609

Exactly, which meant that 850W PSU's were put into an over-spec situation

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.
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November 11, 2013, 03:08:10 AM
 #20610

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

Overspec would be 850/0.9= 944W AC.

And I highly doubt that 850W DC is its maximum anyway.
This review has tested it up to 110% load (934.00W DC / 1032.15W AC) and efficiancy was pretty spectacular: 90.49%
http://www.techpowerup.com/reviews/CoolerMaster/V850/5.html

If this post helped you and you feel generous you know what to do: 1P9tXFy9bVgzrfPGeV7F8np26ZtFdCCWvz
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November 11, 2013, 03:55:31 AM
 #20611

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

Cheers

EtherScan::Ethereum Block Explorer | BlockScan::Coming Soon
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November 11, 2013, 04:02:31 AM
 #20612

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

Cheers

no one knows, but supposedly november batch shipping will commence nov. 15.

if i've helped you, donations welcome: 1BwGnrqSjbfJ39mTNrvb257eUSuUP7Pfxh
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November 11, 2013, 04:21:36 AM
 #20613

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

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?)

"All safe deposit boxes in banks or financial institutions have been sealed... and may only be opened in the presence of an agent of the I.R.S." - President F.D. Roosevelt, 1933
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November 11, 2013, 05:14:41 AM
 #20614

So in answer to CYPER's question...hell yes, it was a bad recommendation.  I'm glad I got a 1000W which accounted for KnC's screw-up in power estimation.  Granted, later firmware has rendered the issue moot..but for the initial release it was a swing-and-a-miss by KnC on that 850W recommendation for sure.

900W AC power is within spec of V850 Wink

Even 950W AC will be within spec on 240V Wink

Of CoolerMaster V850, barely @120V....and by virtue of higher efficiency than the corsairs would only show that hypothetical 900W (but still only rated to 840W on +12V) versus a higher value that would be shown by the corsairs at same DC output wattage.  But the Jupiter's were pulling 950-ish and more at the wall at release up through .95 firmware being released.  And the 240V value would actually go the other way with the higher efficiency gained by the voltage jump...the wall wattage would show lower at 240V versus 120 at same DC output.  The Corsair HX850's that some people were buying were definitely out-of-spec at the wattage being pulled during initial product release due to a smaller actual +12V rail wattage than the overall PSU (again 840W) with seemingly no safety margin and slightly lower efficiency (indicating lower quality parts as well as more internal heat generation which can have a cascade effect when pushing the components to absolute limits).  Since KnC didn't recommend a specific brand/model...they just said "850"...I have to say that their overall recommendation was faulty and was the cause of several failures.

edited to better show train of logic in statements
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November 11, 2013, 05:29:58 AM
 #20615

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

Overspec would be 850/0.9= 944W AC.

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.
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November 11, 2013, 05:33:47 AM
 #20616

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

Cheers

no one knows, but supposedly november batch shipping will commence nov. 15.

Bitcoinorama replied to a PM with the following over the weekend re delivery of a Nov order placed now (and whether they were already manufacturing and stockpiling for immediate delivery)

Quote
Complete shut down.

Boards are being tweaked and revised.

Production is scheduled to commence mid-Nov, which is only a week away. So I personally am not 100% what that means with delivery but it should be late November in your hands, but don't hold me to that as they're trying a few things different now they've had some time to play.
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November 11, 2013, 05:36:54 AM
 #20617

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.

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.

Quote
Again, according to manufacturer's specs you could expect 87.73% @115V input.  So put the lower actual rated rail wattage coupled with lower real-world efficiency 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.

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!   
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November 11, 2013, 05:39:34 AM
 #20618

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

Overspec would be 850/0.9= 944W AC.

And I highly doubt that 850W DC is its maximum anyway.
This review has tested it up to 110% load (934.00W DC / 1032.15W AC) and efficiancy was pretty spectacular: 90.49%
http://www.techpowerup.com/reviews/CoolerMaster/V850/5.html

Great, what about all the other brands and models @850W?  KnC never specified V850's..they just told people to get an 850W power supply.  Some of them (HX850) were obviously not up to the task.
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November 11, 2013, 05:41:29 AM
 #20619

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

No the best efficiency is near the middle load. Get a bigger power supply than you need. It will save money on energy, run cooler and quieter, and probably last longer. Also if you can run on 240, that gives another few percent usually.

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November 11, 2013, 05:42:21 AM
 #20620

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

Overspec would be 850/0.9= 944W AC.

And I highly doubt that 850W DC is its maximum anyway.
This review has tested it up to 110% load (934.00W DC / 1032.15W AC) and efficiancy was pretty spectacular: 90.49%
http://www.techpowerup.com/reviews/CoolerMaster/V850/5.html

Great, what about all the other brands and models @850W?  KnC never specified V850's..they just told people to get an 850W power supply.  Some of them (HX850) were obviously not up to the task.
RM850 and HX1050 and Seasonic 1050 are all working well for me.
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