Hacking The KNC Firmware: Overclocking

[proclivity]

Elenelen

The pic I promised.

Beware NSFW!
Shows VRMs running nekkid in the breeze while quaffing bootleg current at an open bar

https://i.imgur.com/LhXa182.jpg

YMMV

nice soldering job n wire management yep no burnt pcie connectors for you...now ya just gotta figure out how to oc above 500mhz n yer golden...shouldn't take you too long thou

Thx, It works well.

The other end of the 12AWG wires

https://i.imgur.com/epKz23R.jpg

2kW x 2 load sharing on a single rail.
Runs on 1 in a pinch but at the limit and down to only 89% efficiency.
I got space and more PSU for other Nep but will replicate 2kW x 2.
8kW single rail and I don't need to meet personally at my home.

It has a jacuzzi. (top center)
https://i.imgur.com/jeIRRcw.jpg

Also note (lower right) easy access for small children to experience 120VAC firsthand.
Not TOO easy though, short ones must use available step stool.

And a heated outdoor patio. (or garage)
https://i.imgur.com/itLOTSL.jpg

The business end of the loop running during construction.
https://i.imgur.com/r2Qjrig.jpg

I constructed a pentagon and recited the verse and all that appeared was an empty V8 bottle.
https://i.imgur.com/9T8lRc2.jpg

I might flip the PCB so WB are inside of pentagon with straight barbs for smaller footprint.

I usually refrain from prototype pics, but this prototype is less ugly than most of my monstrosities.
I hope to approach the 'pair of WC Saturns complete with PSUs in one case' level of fit and finish.

YMMV

Wow.. I'm inspired to pull out my soldering iron! I'm definitely going to implement the terminal blocks, I've got way too much heat coming off of my power leads, even with a box fan. It's just asking for trouble.

Really great job!

I recommend leaving the WBs facing out. If you do get a failure, facing out should reduce the chance of fluid reaching the other boards.

[1714217157]

1714217157

[1714217157]

1714217157

[tolip_wen]

Draw a matrix with 5 rows and 4 columns on paper, label the 5 rows for each of your numbered ASICs minus one. I had to remove the display panel so my ASICs on the advanced tab were 1, 2, 3, 5 and 6.. (port 4 doesn't work on this card) so I labeled my rows 0, 1, 2, 4 and 5. Label the columns 0, 1, 2 and 3.

I have done similar with Oct ASIC

So much in fact that I slightly automated it (still partly manual but @ kbd instead of pencil)

Preface:
DANGER WILL ROBINSON
The /config folder can save things past reboot.
Just like a normal disk drive.
It is NOT a disk drive and wears out faster.
If you log on Jup or Nep can preserve 'disk' life by using /tmp
It's RAM though, only preserves data if you copy to /config before reboot.
Only suitable for need it now kind of logging but saves lots of write cycles on 'disk'.
Advice is not don't do it, it is don't do it always!
ecaferP

Here is another
What I did
What I wish I had done and why story

I used 'tee' to run SSH to save all output into a file for x minutes.
then I used 'sed' and 'grep' to squink out the details I wanted.
My file required cleanup before it was close to similar to screen.
(due to unseen cursor control chrs being also captured with 'tee' method)

I should have used the logging feature of miner prog instead.

Either way at some point you get a file that looks similar to scrolling data from miner prog.

then I use 'grep' to seperate out only lines with " KnC: " and save them to a new file.
(the errors)

then play

can 'sort' on different fields in each line to see them in core# order (and save to another file)
A glance at that indicates frequency, some core have less entries.

can 'sort' by 2 fields, core then time, etc.
Can count lines with specific core or die or whatever.

can clean up lines with 'sed'.
can switch spaces to comma (with 'sed') and then import CSV into spreadsheet.

If you save to unique self explanitory filename at each step can rebranch from anywhere in chain for new details

Not easier just different.
Save a tree, waste 10 hours learning what you may never use again

I still grab a pen and paper and move the kbd.
It's why I always find envelopes with wierd numbers and hieroglyphs on them.
I musta been outta envelopes.

YMMV

[tolip_wen]

Wow.. I'm inspired to pull out my soldering iron! I'm definitely going to implement the terminal blocks, I've got way too much heat coming off of my power leads, even with a box fan. It's just asking for trouble.

Really great job!

I recommend leaving the WBs facing out. If you do get a failure, facing out should reduce the chance of fluid reaching the other boards.

The blocks I used are (RELATIVELY) inexpensive GROUND strips.
Notice the hazardous wood and tywraps insulating it? I have a cover too.
Actually with formed 12AWG wire I'll have trouble perma-mounting except exactly there.
They come in different lengths depending on power panel size.
One could be cut for 12V and ground for 1/2 price.
Keep in mind they are NOT copper.
I do not put all PSU at one end and all ASIC at other.
I have 4 12V wires per PSU, one from each PSU together every 4 holes.
(abandoned plan for 8kW rail)


Regarding solder and ASIC PCB power pins:
Go big(with iron wattage and iron tip) or stay home.

Although my fancy dancy 18AWG to each VRM was planned exactly as pictured,
it was not scheduled for when it was installed.
And I brought big iron to the game, plus preheat PCB.

One of my PCIe connector 12V pins was not soldered well originally. fact.
(many in fact did not flow to top of PCB along pin, do they scrimp on Silver too?)
I in egotistical self defense might claim the hole was full of slag and wouldn't clean up.conjecture
Everyone else could safely assume the 12V pins might require caution and TLC.
I still had connection but no trust that is was not compromised, creating what I sought to avoid HEAT.
If I had a do-over I would have cut or melted the plastic out of the way to preserve the pins and vias.
Or left it alone to begin with.
The ground pins are quite sturdy even with 1/2 filled holes.

A third decent option exists for applying 12V to PCB.
Between VRM PCB and outer caps on ASIC PCB is 12V. Inside of cap from edge of ASIC PCB.
(exception C26 & C27 hot is toward edge of ASIC PCB)
It looks like in all instances 12V is the side opposite the silkscreen designators.
It's a tight space but could get by with lower wattage iron if you just attach small wires to inside of some 12v caps.
If you have enough heat to wick em clean on one side you have good sturdy corner to put wire and resolder caps.
Only clean one side of caps and caps will provide mount point. dirty would also work if ya have no wick.
Reflow one cap at a time and neighbors can provide oops support.
Would not need to have wire extend past more than 2-3 caps.
No idea what signals are on VRM PCB in that area so I'd avoid getting too close.
2 18AWG PCIe cables cut and sacrificed gives ya 6, could skip the ones by connector and plug in more power(or not).
Could probably skip and reasonably backfeed 1/2 the VRMs from neighbors.
A single 18AWG  PCIe(sacrificed) to the 3 farthest VRMs would help a LOT.
Some 28nm folks might already have unmelted blue extenders just begging to be cut.

I'm anal about potential points of failure that create lots of HEAT when they occur unattended.
Add crimps and consider 2 ends of every wire on modular PSU and it becomes a puckerful motivation for me.
30+ potential points of failure per ASIC (PPOFPA)
I'll never use a modular cable PSU with high current again if possible.


RE: fluid on PCB
tested
Takes a couple hours to reawaken some VRMs
They neighbors bake-em-awake.
Choose fluid and additives wisely!
If it leaks after construction in a static state I got other issues though inside or outside.

Life is full of options!

YMMV

[Elenelen]

Regarding solder and ASIC PCB power pins:
Go big(with iron wattage and iron tip) or stay home.

And I brought big iron to the game, plus preheat PCB.

One of my PCIe connector 12V pins was not soldered well originally. fact.
(many in fact did not flow to top of PCB along pin, do they scrimp on Silver too?)

That's also my experience: the solder on the PCIe connectors doesn't melt well (or not at all)... the first additional plug I soldered on the backside of the board, just melted the plastic of the plug itself while the original PCB-solder was still hard... I had to plug in a PCI-cable into the plug first, to function as a heat sink. This worked more or less, but still wonder how well (or bad) the solder joined...maybe I need to redo it with a bigger Iron?  What wattage did you use?

[jelin1984]

final which is avg speed of neptune when push it at 500mhz?

[Elenelen]

final which is avg speed of neptune when push it at 500mhz?

My, cgminer Average with running it 2 days: 3.483 Th/s  and 48667 WU

[jelin1984]

Still no high a lot

[tolip_wen]

That's also my experience: the solder on the PCIe connectors doesn't melt well (or not at all)... the first additional plug I soldered on the backside of the board, just melted the plastic of the plug itself while the original PCB-solder was still hard... I had to plug in a PCI-cable into the plug first, to function as a heat sink. This worked more or less, but still wonder how well (or bad) the solder joined...maybe I need to redo it with a bigger Iron?  What wattage did you use?

First PCB I did with a Radio Shack 40W iron with a huge perfect tip.
It worked OK was prepared for a struggle and it was.
I raised the PCB with some hot air too.
If it did not flow quickly I stopped and let the tip reheat.

I destroyed the tip and flipped on the workstation to 896F wattage unknown but 70-100 ish.
WIth the ground pins you are also fighting the top, bottom, middle gnd??? layers.
One reason I nixed the plastic, end of mostly straightened pins was much easier target.
I was also dealing with 2 long 12AWG heatsink wires per 3 pins (thourogly fluxed and pre-tinned).

I'd suggest 75+ if you have a choice, use what you have if reasonable.
I don't recommend guns but cheap spares for rude big stuff are.
http://www.homedepot.com/p/Weller-75-Watt-Soldering-Gun-Kit-7200PKS/100143633
http://www.homedepot.com/p/Weller-100-140-Watt-Soldering-Gun-Kit-8200PKS/100085564

I have an old 200/260 monster that I inherited, not too big for the power connections if ya don't lurk forever.

OBTW
Got me VRMs 70s mid80s instead of 80s, upper90s, and ker plink 0 watt ambient PCB temp.
Still just nekkid in the breeze but I added a playing card sized piece of cardboard to WB on upwind side to offset the WB obstruction.

Weeee, now I could coast on cooling till faster clock magically appears.
I still have one more speed on AC box fan.

YMMV


EDIT
If anyone is interested I had an idea for stock parts survival lunch.
I put it there as it probably applies to all nep owners not just OC folks.

https://bitcointalk.org/index.php?topic=170332.msg7727618#msg7727618

[Elenelen]

That's also my experience: the solder on the PCIe connectors doesn't melt well (or not at all)... the first additional plug I soldered on the backside of the board, just melted the plastic of the plug itself while the original PCB-solder was still hard... I had to plug in a PCI-cable into the plug first, to function as a heat sink. This worked more or less, but still wonder how well (or bad) the solder joined...maybe I need to redo it with a bigger Iron?  What wattage did you use?

First PCB I did with a Radio Shack 40W iron with a huge perfect tip.
It worked OK was prepared for a struggle and it was.
I raised the PCB with some hot air too.
If it did not flow quickly I stopped and let the tip reheat.

I destroyed the tip and flipped on the workstation to 896F wattage unknown but 70-100 ish.
WIth the ground pins you are also fighting the top, bottom, middle gnd??? layers.
One reason I nixed the plastic, end of mostly straightened pins was much easier target.
I was also dealing with 2 long 12AWG heatsink wires per 3 pins (thourogly fluxed and pre-tinned).

I'd suggest 75+ if you have a choice, use what you have if reasonable.
I don't recommend guns but cheap spares for rude big stuff are.
http://www.homedepot.com/p/Weller-75-Watt-Soldering-Gun-Kit-7200PKS/100143633
http://www.homedepot.com/p/Weller-100-140-Watt-Soldering-Gun-Kit-8200PKS/100085564

I have an old 200/260 monster that I inherited, not too big for the power connections if ya don't lurk forever.

OBTW
Got me VRMs 70s mid80s instead of 80s, upper90s, and ker plink 0 watt ambient PCB temp.
Still just nekkid in the breeze but I added a playing card sized piece of cardboard to WB on upwind side to offset the WB obstruction.

Weeee, now I could coast on cooling till faster clock magically appears.
I still have one more speed on AC box fan.

YMMV


EDIT
If anyone is interested I had an idea for stock parts survival lunch.
I put it there as it probably applies to all nep owners not just OC folks.

https://bitcointalk.org/index.php?topic=170332.msg7727618#msg7727618

Thanks... this explains a lot... I did it with a 16 Watt... I will order a larger one now.

[tzortz]

I think air soldering is better in that case.

[tolip_wen]

Thanks... this explains a lot... I did it with a 16 Watt... I will order a larger one now.

16W may not melt thru all solder in the via/hole.
Quite acceptable for your method but hard to get it just so.
You must have the knack for it and more patience than me.
If you did it with 16, 40 will be enough for you forever, exception big power circuits.
Heavy tips help lots too if ya git er done quick, some spare heat!
(PSU, thumper amps, soldering AC wiring, etc.)

If it works it works.

A bit of time/frustration vs additional tool money, depends on budget/frequency of use.

YMMV

[proclivity]

I believe is the difference in your construction appliance.

If you had a thermal camera, you could see it.

Or measure (beam measure?) the heatsink and the vrm temps of all of them.
If you see great difference between vrm/heatsink , then there is bad thermal contact.

I am sick of KNC, need so much babysitting.

Have you watched my photo's ?   all VRM's are more or less modified with Heatsinks in the same way. especially #4 and 5 are just infront of the Fan.
And NO there is no bad terminal contact: that would be very odd to have 4 x 5boxes = 20 VRM's all on the same PCB-side, having bad terminal contacts and the other 20 on the left side not... so that's not a logical explanation.



I know this photo is from one of the boxes which has a few more heatsink-fins on VRM-5 than VRM-4, but with my other 4 boxes, both heatsink sizes are the very same, and all those boxes have the same problem: all four VRM's on the right-side are 10 degrees hotter than the left-side.... I have no logical explanation...

I've got the exact same behavior.. DC/DC 0-3 are easily 10C hotter then DC/DC 4-7 and I don't have any special features beyond an external box fan. I know you don't think it is, but a voltage drop in the board itself delivering lower input voltage to the VRMs would cause higher current/heat.. maybe the bus is a little undersized that feeds those 4.. only a guess. Could also be a firmware issue.

tolip_wen.. would be very interested to know if you see this with your VRMs and the dedicate power runs?

[Elenelen]

I've got the exact same behavior.. DC/DC 0-3 are easily 10C hotter then DC/DC 4-7 and I don't have any special features beyond an external box fan. I know you don't think it is, but a voltage drop in the board itself delivering lower input voltage to the VRMs would cause higher current/heat.. maybe the bus is a little undersized that feeds those 4.. only a guess. Could also be a firmware issue.

tolip_wen.. would be very interested to know if you see this with your VRMs and the dedicate power runs?

I now think that numbering is from right-top (1), left-top(2), right-middle(3), left-middle(4)...and than 5--8 on the front of the Fan....But we need to test that still (no time yet...)

[Elenelen]

Thanks... this explains a lot... I did it with a 16 Watt... I will order a larger one now.

16W may not melt thru all solder in the via/hole.
Quite acceptable for your method but hard to get it just so.
You must have the knack for it and more patience than me.
If you did it with 16, 40 will be enough for you forever, exception big power circuits.
Heavy tips help lots too if ya git er done quick, some spare heat!
(PSU, thumper amps, soldering AC wiring, etc.)

If it works it works.

A bit of time/frustration vs additional tool money, depends on budget/frequency of use.

YMMV

Yep... I managed to "plumb" the plug on top of the  PCB-pins... but I know, it could be done much better with a hotter iron.

I will buy something like this:
http://www.ersa.com/art-0710cd-358-5046.html

[tolip_wen]

I've got the exact same behavior.. DC/DC 0-3 are easily 10C hotter then DC/DC 4-7 and I don't have any special features beyond an external box fan. I know you don't think it is, but a voltage drop in the board itself delivering lower input voltage to the VRMs would cause higher current/heat.. maybe the bus is a little undersized that feeds those 4.. only a guess. Could also be a firmware issue.

tolip_wen.. would be very interested to know if you see this with your VRMs and the dedicate power runs?

Same trend, glad I had other reason for mod.
Voltage is same everywhere on PCB to 2 decimal places on 20V scale.
12.01VDC delivered @ connector and VRM. my rail is 12.09 so even 2x12AWG is hungry wire.
I measured from rail to VRM filter caps and connector to caps all side VRMs. modded and unmodded boards.

Based on fan direction and twist of airflow,
the right may be in the wind shadow of hot heatpipes.
Might get more air downstairs on one side too.
Downwind are the hottest, pre heated coolant.

Cardboard origami twist reducing baffles to test?
(small glass xmas ornament box seperator like thingies)
Plug leaks past top of heatsink foam! no question wasted air
Tape across some ASIC heatsink fins to trade ASIC air for VRM air?
Restrict one side till even?

A warmer side of ASIC would do something too.
The heatsink is about 35mm^2 on about a 40mm^2 heatspreader.
The alignment holes are larger than alignment screws.
Did we all happen to tighten screw closest to connector before farther one or vice-versa?
The top of the ASIC are not perfectly flat, high in middle mine are.
Can see the PCB warp, one side might warp less?.
I recall the bumps being oval but not orientation.
Was just glad it was high and not low, less to remove to make flat.

Without bfgminer, looking for core trends is painful at best from cgminer output.
Can find hotspots with bfg on 28 easy.

MOST chip lids are not flat, but most not over 300W thru less than 16cm^2 heatspreader either.

A VRM reflow issue on that side of PCB? It's gotta drive reflow setup guys nuts them things.

Good mystery!

YMMV

[tolip_wen]

I've got the exact same behavior.. DC/DC 0-3 are easily 10C hotter then DC/DC 4-7 and I don't have any special features beyond an external box fan. I know you don't think it is, but a voltage drop in the board itself delivering lower input voltage to the VRMs would cause higher current/heat.. maybe the bus is a little undersized that feeds those 4.. only a guess. Could also be a firmware issue.

tolip_wen.. would be very interested to know if you see this with your VRMs and the dedicate power runs?

I now think that numbering is from right-top (1), left-top(2), right-middle(3), left-middle(4)...and than 5--8 on the front of the Fan....But we need to test that still (no time yet...)

If that were true wouldn't the low V going from #0 (number one's buddy for first die) take a much longer route to same quadrant of ASIC? That distance is so critical that they make sure VRM has output on correct side for shortest run.
Also not symmetrical left/right possibly indicating low V distance priority.
The low V high current traces might be different on that side.
The goal may not have been fully met for some reason.

1 and 0 are likely top right and directly below in that order IMneverHO.

That Iron looks comfy!
Pictured tip has cylindrical room to add more mass with big wire and pliers if ya ever needed such a thing.
A well tinned tip KNOWS somehow if you have a spare tip and lasts longer in self preservation BTW
Finagles Law

YMMV


EDIT the one in the lower right is turned sub optimally for low V, possibly optimized for 12V only?
Temps marginally say 2 is a tad warmer than 3 sample size 5.

[proclivity]

Same trend, glad I had other reason for mod.

Thanks for having a look! A good mystery indeed.. Will tinker with airflow some more this week, I've already plugged the leaks at the top (with no measurable benefit unfortunately).

[bitpop]

What do you think about potting the entire thing then putting it into running water? A giant cheap water cooler

[Elenelen]

After 2.5 days running with Volt-tuned 500 Mhz, this is what currently is possible: 3.500 Th/s

[proclivity]

What do you think about potting the entire thing then putting it into running water? A giant cheap water cooler

sounds interesting.. i look forward to your write up! this would certainly void the warranty.

i am (seriously) considering piping water in a loop from my pool and using that as a 30,000 gallon heat sink

i even bought a variable speed pool pump so i can run it 24/7 at a moderate flow rate. just need to work out a few kinks linking WC parts together and how to safely run water through my attic.