Swedish ASIC miner company kncminer.com

[texaslabrat]

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.

[smooth]

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.

[bobsag3]

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.

[DeathAndTaxes]

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.

Typo.  I was saying at most the PSU will be 90% efficient.   Still the efficiency curve on a modern "80-Plus" PSU is very very flat, almost a horizontal line.   The difference between 50% load and 80% load is usually 1%.  It isn't going to run significantly cooler, last significantly longer, or save any meaningful amount of power.  Key word meaningful be sure to compare any savings to the cost of oversizing the PSU.  It isn't the 1980s anymore.  PSU have gotten a lot better in the past 3 decades.

[DeathAndTaxes]

Of CoolerMaster V850, barely @120V by virtue of higher efficiency than the corsairs (but still only rated to 840W on +12V).  But the Jupiter's were pulling 950-ish at the wall at release up through .95 firmware being released.  The Corsair HX850's that some people were buying were definitely out-of-spec at that wattage due to a smaller actual +12V rail wattage than the overall PSU (again 840W) and slightly lower efficiency.

EFFICIENCY DOESN'T CHANGE THE DC LOAD.  IT ONLY CHANGES HOW MUCH MORE POWER IS USED ON AC SIDE.

AC LOAD = DC LOAD / EFFICIENCY. 
SO LOWER EFFCIENCY = HIGHER AC LOAD FOR THE SAME DC LOAD.
SO AN 800W DC LOAD is ALWAYS GOING TO BE 800W DC. POWER SUPPLIES ARE RATED BASED ON THE DC LOAD.  

[texaslabrat]

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.  Strange KNC entire datacenter is powered by nothing by 850W PSU.  KNC still recommend 850W.  Many people are using 850W PSU without issue.  

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.  That is about 100W higher than any has reported their unit pulling.

Actually, I have a degree in Engineering and I do technology work for a living...math is very much my strong suit.  I'm telling you that those PSU's (HX850) were shutting off.  I just reported to you that mine ran 950W constantly (bounced between 945 and 954) as I watched it in real time.  I have seen momentary spikes up to about 975W (read 972 briefly when it happened). Since my UPS only seems to report wattage in 9W increments, it very well may have been higher.  I'm pretty sure I don't have a "special unit".  It's obvious (to me, at least, who seems to actually understand these things) that the failure mode related to the HX850 was caused by overcurrent protection kicking in.  This failure mode could have been prevented by buying a 1000W PSU, as many people did (and those who had HX1000 reported no such problems to my knowledge).  Now, you can play armchair engineer all day (as you are apt to do on these threads, and often talk out of your ass though few call you on it) but that is a fact.  That is something that GE themselves verified with a hands-on test.

As for "strange" blah blah blah...um, you don't happen to remember the OTHER datacenter that had numerous boards blow up because they were running HX850's?  Seriously dude, did you hit your head or are you just trying to be a revisionist historian here to serve some sort of agenda?  Look back at the thread...all the info is there in gory detail.  The fact that 1) KnC lucked out by using Coolermaster which seemed to have a bit of headroom in the specs and more tolerant overall and 2) they quickly released firmware which dramatically reduced power requirements has been the reason(s) that they haven't had catastrophic issues.  

And to specifically address the "nonsense" thing...you sure talk with a lot of authority on how these things operate for someone who doesn't even have one.  But I guess it's easier to just theorize rather than deal with actual facts gained from hands-on observations, right? 

[texaslabrat]

Of CoolerMaster V850, barely @120V by virtue of higher efficiency than the corsairs (but still only rated to 840W on +12V).  But the Jupiter's were pulling 950-ish at the wall at release up through .95 firmware being released.  The Corsair HX850's that some people were buying were definitely out-of-spec at that wattage due to a smaller actual +12V rail wattage than the overall PSU (again 840W) and slightly lower efficiency.

EFFICIENCY DOESN'T CHANGE THE DC LOAD.  IT ONLY CHANGES HOW MUCH MORE POWER IS USED ON AC SIDE.

SO AN 800W DC is ALWAYS GOING TO BE 800W DC. POWER SUPPLIES ARE RATED BASED ON THE DC LOAD.  THE AC LOAD WILL BE HIGHER, THE LOWER THE EFFICIENCY THE HIGHER IT WILL BE BUT THAT DOESN'T CHANGE WHAT THE DC LOAD WAS.

BUT WHEN YOU CALCULATE BACKWARDS FROM A WALL WATTAGE TO A DC WATTAGE, YOU USE THE EFFICIENCY RATING TO DO SO AND SINCE CYPER QUOTED A WALL WATTAGE IN HIS STATEMENT OF BEING IN SPEC, IT IS APROPOS TO USE THE EFFICIENCY AS PART OF THE SUPPORTING DATA.  IN ADDITION, IT IS PROBABLE THAT THE COOLERMASTER UNITS HAVE A MARGIN BUILT INTO THEIR 840 RATING WHEREAS THE CORSAIR UNITS OBVIOUSLY DID NOT.

All caps is fun, does that make me as cool as you think you are?

[texaslabrat]

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.

Awesome  Coolermaster V1000 working great for me as well.  Lots of sad people who took Day 1 and Day 2 deliveries with corsair HX850's were not as pleased with the results.  These days with the new firmware, non-issue thankfully.

[DeathAndTaxes]

BUT WHEN YOU CALCULATE BACKWARDS FROM A WALL WATTAGE TO A DC WATTAGE, YOU USE THE EFFICIENCY RATING TO DO SO

Which wasn't the point.  Saying "Of CoolerMaster V850, barely @120V by virtue of higher efficiency" is nonsense.  The efficiency of the power supply has absolutely nothing to do with what DC load it can handle.  Nothing.  The only difference between a 850W 90% efficient unit and a 850W 20% efficient unit is how much additional AC power is used to generate the same amount of DC power.

The DC load isn't going to change, the ability of the PSU to handle that DC load isn't going to change.

You also seem to not grasp that LOWER efficiency means for a given observed AC load the DC load is even lower.   You corrected my use of a (intentionally) high 90% efficiency to point out it was "only 87%" when the 3% lower efficiency only means the DC load was EVEN LOWER for a given observed AC load.  If a unit isn't over spec at 90% efficiency it isn't going to be over spec at 87% efficiency or 1% efficiency.

[texaslabrat]

However saying "Of CoolerMaster V850, barely @120V by virtue of higher efficiency" is nonsense.

Higher or lower efficiency only changes how much extra power is used on the AC side.  Take the lowest efficiency and highest efficiency power supply in the world and the DC load is going to be exactly the same.

You also seem to not grasp that LOWER efficiency means for a given observed AC load the DC load is even lower.   You correct my use of a (intentionally) high 90% efficiency to point out it was "only 87%" when the lower efficiency would simply mean the DC load was EVEN LOWER.  If a unit isn't over spec at 90% efficiency it isn't going to be over spec at 87% efficiency or 1% efficiency.

I understand what you are saying, but when CYPER starts with a wall wattage and says it is "in within specs" you use the efficiency to work backwards from that to find the DC output wattage and therefore if it is within the 840 listed.  The entire exercise is a "paper" one, but that's what he presented so that's what I gave him back.

And I "grasp" all of this fine, thanks.  You don't seem to grasp what I was trying to convey to CYPER.  Read the prior paragraph a few times and let it sink in.  You are picking an argument where there is none.  I will admit that I did not "show my work" and list in exhaustive detail all the "givens" that went into my statement to your satisfaction since I was just trying to fire off a quick blurb to him, and not you.  But if you want it:  here is more for you.  CYPER listed 900W and said the V850 was in spec.  Because of the higher efficiency, it only showed 900W at the wall whereas a HX850 would have shown slightly more owing to its lower efficiency.  At 900W, at the listed 90% typical and 93% efficiency at fifty percent load, I used the 90% figure to arrive at a value of 810W DC and thus it was in spec at that wall wattage (though barely..I consider a headroom of 30W to be riding the razor's edge at that level).  Obviously, I should have put in a caveat that I would expect the HX to show a higher wall wattage at a similar DC load, and also go into gruesome detail (as I did in the exchange with you later on) about my own observations of *actual* steady sustained and spike power that I observed (although I thought I was alluding to that fact, but perhaps I was too vague).  I did not do that, and I apologize that it confused you.  Better?

The reality is that those machines pulled more at the wall than what he even cited at times, and thus were out of spec on the spikes rendering that hypothetical exchange moot.  Thankfully (for KnC's hosted miners and others) CoolerMaster "V" series units didn't shit themselves and handled the load.  The HX850 units (or at least a number of them) did not conduct themselves in the same stalwart nature.  At the end of the day, as is my only argument all along,  a blanket "850W PSU" recommendation was insufficient and it wound up causing issues.  KnC later fixed it with firmware..yay for them..but the initial information missed the mark.  

[smooth]

Typo.  I was saying at worst the PSU was 90% efficient.  Still the efficiency curve on modern PSU is very very flat almost a horizontal line.

That's misleading

The difference between 50% load and 80% load is usually 1%.

Between 50% and 80% maybe but look at the chart references on this thread a few posts back (not by me so I'm not cherry picking). http://www.techpowerup.com/reviews/CoolerMaster/V850/5.html

If you go up to 100% you are down 2% from 40% or 50%, not 1%. But this is again somewhat misleading, see below.

It isn't going to run significantly cooler, last significantly longer, or save any meaningful amount of power.

It will save about 2% from running at full load or 1% from running at 80%. Even running at 80% is better than 100% though. If you are pulling 1000W 24/7 and paying 5c/kWh then the difference in power alone is $8/year, ignoring the power supply itself running cooler. If you are paying 15c this is $24/year.

Now when it comes to heat produced within the power supply, that ALL comes from the losses. If a power supply is 90% efficient, that is 10% losses. At 88% efficiency that is 12% losses, so 20% more heat, not just 2%. That's definitely significant to the temperature and cooling of the power supply.

I wouldn't pay a lot more for a bigger power supply but I would definitely pay somewhat more.

[DeathAndTaxes]

True I didn't say it was zero just minimal.  Compare the annual savings to the higher PSU cost and you see the break even time is measured in years (possibly a decade at lower wattage and lower power rates).  The flatness of the curve really kills any savings in power costs.  Now prior to 80-Plus program a lot of PSU were junk and the curve was very steep.  If you have a PSU line that has 85% efficiency at 50% load and it collapses to something horribly like 68% efficiency at 90% load the 17% delta in efficiency by is huge.  This is where the "aim for 50% load" rule of thumb came from and while it was good advice at one time, its day has past.

If one wanted to spend more upfront to cut their power bill upgrading to a Platinum PSU and switching to 240V provides a bigger gain.  Platinum PSU is going to be ~3% higher efficiency and 240V is going to improve efficiency by about another 1% to 2%.  For powering a 600W load I would take a highly rated 850W Platinum PSU over a 1250W (or 1500W, 1600W as advocated by some) Gold or lower rated PSU.

[Bitcoinorama]

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.

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!

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

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

[texaslabrat]

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

And I'd be willing to bet a few satoshi's that the unit you took to Atlanta did not have the same firmware as those units that were subsequently shipped out to Day 1 customers onwards...and that the voltage was tweaked upwards in the interim thus increasing the power requirements (in the name of increasing performance/stability, I'm sure).  Couple the fact that the actual physical design of the product was changed quite substantially (8 VRMs to 4 VRMs) and it's not exactly apples-to-apples

Even in the "launch video" you have footage of the kill-a-watt pulling ~850W at the wall at (I assume) 240V with (I assume) 8 VRMs per board.

Not insinuating anything malicious here..just saying that what was put out there ended up being inadequate given the issues that cropped up with some of the 850 PSU's (HX850 that you had so much fun with, for instance).

[Bitcoinorama]

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.

No. There's several hundred of the V850s running in the data centre. I have 3 on my desk, and have at some point used firmwares for, and not for public release. None of those PSUs haven't had anything thrown at them so far, they cannot handle. The 1000w I mentioned was for something entirely different to the Jupiters sold.

[texaslabrat]

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.

No. There's several hundred of the V850s running in the data centre. I have 3 on my desk, and have at some point used firmwares for, and not for public release. None of those PSUs haven't had anything thrown at them so far, they cannot handle. The 1000w I mentioned was for something entirely different to the Jupiters sold.

I've never said that the V850's had problems..I am specifically referring to the corsair HX850's which were the center of the "exploding capacitor" investigation.  By leaving the recommendation so open (generic "850W" recommendation) without actually testing, many customers were set up for failure in the early days of delivery as you well know.  Thankfully, less power-hungry firmware was released later which fixed the issue.

[Biffa]

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

And I'd be willing to bet a few satoshi's that the unit you took to Atlanta did not have the same firmware as those units that were subsequently shipped out to Day 1 customers onwards...and that the voltage was tweaked upwards in the interim thus increasing the power requirements (in the name of increasing performance/stability, I'm sure).  Couple the fact that the actual physical design of the product was changed quite substantially (8 VRMs to 4 VRMs) and it's not exactly apples-to-apples

So basically all you can say is that a few machines that you know of pulled high watts, you don't know how many right?

I'd guess that, relative to the entire Day1/Day2/October production run its probably just a few isolated units caused by manufacturing and/or production tolerances.

I don't know for sure, thats why I am saying "I guess" but at least I'm not making out like it was a huge problem for everyone. Plus it was like Day 1 units, almost prototypes in a way, cutting-edge-get-it-before-anyone type stuff.

Surely the discussion is about now, people coming into the thread recently to find out what they need for the next batch.

[Bitcoinorama]

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

And I'd be willing to bet a few satoshi's that the unit you took to Atlanta did not have the same firmware as those units that were subsequently shipped out to Day 1 customers onwards...and that the voltage was tweaked upwards in the interim thus increasing the power requirements (in the name of increasing performance/stability, I'm sure).  Couple the fact that the actual physical design of the product was changed quite substantially (8 VRMs to 4 VRMs) and it's not exactly apples-to-apples

No, you are wrong. It was a standard unit I made when at the manufacturing facility. By that point I had not seen my hotel for a week, and certainly no one had had anytime or were confident enough to tweak a unit. Literally decided on going. Booked a flight at 11pm, the night before, for an 11am take-off. Then searched for a hotel, made a device, drove several hours back to Stockholm, washed, packed and made my way to the airport. Thing is no way was a clocked machine risked that early. We had only seen the chips 5 days earlier and just had to have something that worked. Why if something performed well, would it not be given to customers. Austin and Beccy Craig from Life on Bitcoin have had it in their possession since that Atlanta conference. Can we please stop this 8/4 VRM nonsense. The additional 4 vrms were surplus to reaching spec. They were in place in the beginning in case they were needed to achieve the spec. They weren't so they aren't.

[texaslabrat]

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

And I'd be willing to bet a few satoshi's that the unit you took to Atlanta did not have the same firmware as those units that were subsequently shipped out to Day 1 customers onwards...and that the voltage was tweaked upwards in the interim thus increasing the power requirements (in the name of increasing performance/stability, I'm sure).  Couple the fact that the actual physical design of the product was changed quite substantially (8 VRMs to 4 VRMs) and it's not exactly apples-to-apples

So basically all you can say is that a few machines that you know of pulled high watts, you don't know how many right?

I'd guess that, relative to the entire Day1/Day2/October production run its probably just a few isolated units caused by manufacturing and/or production tolerances.

I don't know for sure, thats why I am saying "I guess" but at least I'm not making out like it was a huge problem for everyone. Plus it was like Day 1 units, almost prototypes in a way, cutting-edge-get-it-before-anyone type stuff.

Surely the discussion is about now, people coming into the thread recently to find out what they need for the next batch.

I'm saying that all of the Day1/Day2 machines that were delivered with pre-.95 firmware pulled very high wattage..and in some cases that translated to hardware failures when coupled with PSU's like the Corsair HX850 that contributed to exploding capacitors.  Actually testing specific PSU's and making specific recommendations based on known-working models would have been better instead of leaving it to chance for customers to figure it out on their own.  I, myself, bought the same model as KnC's hosting but gave myself some extra margin with higher wattage rating so my machine was never running over-spec of the PSU at any time on any firmware (the VRMs themselves, well, that's another story).

[texaslabrat]

Umm, that's cool, but I can assure you not that's clearly not he case on all units. I have pictures of the one I took to Atlanta using a Kill-A-Watt, and there were enough witnesses that were present, including members of this forum (Bargraphics, Phin Gage), and representatives from competing companies that saw this for their own eyes. Also there's plenty in this thread amongst the first recipients to verify otherwise.

And I'd be willing to bet a few satoshi's that the unit you took to Atlanta did not have the same firmware as those units that were subsequently shipped out to Day 1 customers onwards...and that the voltage was tweaked upwards in the interim thus increasing the power requirements (in the name of increasing performance/stability, I'm sure).  Couple the fact that the actual physical design of the product was changed quite substantially (8 VRMs to 4 VRMs) and it's not exactly apples-to-apples

No, you are wrong. It was a standard unit I made when at the manufacturing facility. By that point I had not seen my hotel for a week, and certainly no one had had anytime or were confident enough to tweak a unit. Literally decided on going. Booked a flight at 11pm, the night before, for an 11am take-off. Then searched for a hotel, made a device, drove several hours back to Stockholm, washed, packed and made my way to the airport. Thing is no way was a clocked machine risked that early. We had only seen the chips 5 days earlier and just had to have something that worked. Why if something performed well, would it not be given to customers. Austin and Beccy Craig from Life on Bitcoin have had it in their possession since that Atlanta conference. Can we please stop this 8/4 VRM nonsense. The additional 4 vrms were surplus to reaching spec. They were in place in the beginning in case they were needed to achieve the spec. They weren't so they aren't.

Well that is surprising given the results that later cropped up with overcurrent PSU's and exploding capacitors..do you have a link to those kill-a-watt photos from Atlanta?  I don't remember the values you saw there versus what was in the youtube video in Sweden.  And just to clarify..when I said "tweaked" I meant subsequent production machines, not the one you took to Atlanta.  In other words, my assumption was that the initial "beta" firmware or whatever you had then was running at say .8V and then when you guys decided on the production values for the boxes that were going to start shipping it was bumped to .9V for the added stability/speed benefits that brings.  I wasn't suggesting that you custom-tuned the Atlanta box.  But however it worked out in the order of events...there were definitely some growing pains in relation to power at the PSU and the power through the VRMs that had to be ironed out, as I know you are extremely familiar with

As for the 8/4 thing...well, you keep saying it didn't matter when the facts showed that it did.  There was a material difference in how those things ran before/after the change which had to be accounted for in new firmware.  Again, I don't think it was some malicious conspiracy or anything..but I do think it was a reckless change that was done without adequate testing which caused issues that had to be addressed further down the road.