This stuff is so efficient that surface area would not come into play unless you're wanting to push something like (wildly guessing here) 1kW through a 25x25mm chip.


Similar in that it's a phase change system, yea; not sure on the specifics.


This is known as open bath so in theory no lid is required (but in practice an almost air tight lid is advisable); where water is 1kg per 1L Novec 7100 is about 1.35kg for 1L and the same goes for the gas once it evaporates it is much heavier than air. Once the layer of HFE gas is thick enough to reach the cooling it condenses and drips back down to replenish the bath.


His rig has seen some changes since, but I took these when I first got eyes on his test setup. Not really showing anything different to smracer video:

http://videobam.com/MduAt













EDIT:
Other VRM's eventually get much hotter and some clocks reduced to keep a handle on VRM temps; but the board in Novec can just be adjusted for max speed up to 51A(ish):


He needs to get the clocks running faster but neither he or I have any idea where to start; can we get a noobs guide to 525Mhz?

u27

I did! Just confirming your findings match my friend's results.


That's not how evap cooling works; the bath is at 60 degrees and as soon as anything gets above that the liquid boils carrying the heat away. Heat sinks go at the other end of the system to cool the water in the loop.

u27

I did go into the shop and ask for the coolest cable they had; regardless of any possible homosexual cogitations. They sure delivered.

u27

I'm working on cooling, but a friend beat me to it with the Novec 7100... Screenshot below showing comparison between stock cooling and evap. cooling/

He say's VRM's shut down from time to time at the voltage shown so confirmed 51A is the limit regardless of temps the OCP cuts in; he is running at 500 with one voltage setting above stock now without any problems.

Serial cable problem solved; made some double length ones.

I swapped out two of the ridiculously short KfC cables and the whole cable layout is much more comfortable now. I have the parts to make another dozen if anybody needs them in the UK.

Comparison:


Action shot:

Same shit, different Neptune:

Can you back that statement up with anything concrete? They admitted to "we hash while you wait" but only for what they described as testing; they could (should) have configured customers miner details for this testing so everybody would see a couple hours of shares come through the day before their miners were dispatched... But I don't believe they were running Neptunes in ze dator haal and then meticulously cleaning the fan dust from between the heat sink fins for instance.

u27

I think you are correct there. Plus KnC have been historically honest (we think) about their level of hashing; even when it exceeds their "never hash with more than 5% of what we sell" to the extent of 5% whole network.

Also, were you in lock stock?

I did see that Neptune board in 7100; looks suspiciously similar to the giant lab beaker I intend to use.

I will work on uber cooling the rig; hope to see some custom overclock-able firmware by the time I'm done.

I figured it was 0.77v or whatever from VRM one side and then -0.0366v the other so -0.0439 was actually pulling more voltage across the chip. But you are clearly correct in that it simply modified the default voltage and the other side of the chip stays at 0v.

Thanks

Novec 7000 would be a massive cooling headache; 7100 is much more feasible.

Depends how big your bottle is; you could put a hundred of them in one tank if your tank was big enough and your cooling could keep up.


-0.0439 means you're pulling a higher voltage across the chip or not?

What is OCP? (please excuse my ignorance)

How super cool are we talking? Pretty sure the Novec would still keep them at 65 if you were running 100A through them/

EDIT:
Over Current Protection right?

One system is fine; water loop just moves the heat from the condensing rad to the cooling rad.

EDIT:
A friend has managed to get a Neptune board up and running in Novec 7100 now:

This is all looking very promising; custom firmware with a "kick sleeping VRM's" button would be really sweet.

Let me know if I can do anything to help; my Novec 7100 just arrived but the tank is not here yet. I'm going to leave it well alone until KfC sort out my dead die issues and then throw one of them in the Novec for consistent 65 degree running across the board. Do we think that the VRM's will tolerate 50A+ if they are properly cooled?

u27

Seriously? I think it is now generally accepted that nobody is going to read this whole thread having joined the party late; it's just not practical any more.

Also (if you sifted around the last few pages of this thread you would see) the web front end was not working properly for me and I thought I heard an SD mentioned.

I do appreciate all the work you guys did fixing KfC blunders on the last generation/

I do try to help people out when sometimes I know stuff; so it's nice to be able to ask a simple question that's going to take somebody 2 seconds to answer rather than actually being competent with *nux.

Long story short; doing things on my own is hard


Sorry aasl, the guys are correct. The benefit of the cables I made is that they take the 12v power from PSU to PCI-e through 16 cables thus spreading the load. The cablex ones use 12 thicker cables to carry the power to the PCI-e so either way tons of capacity. Your molex to PCI-e on the other hand uses four cables (two out of the six are 5v I think) thus making it 50% worse than the KfC effort using six cables. In order to make a molex to PCI-e which would be as effective as one of the cablex 2to1 PCI-e you would would have to make a 6to1 molex to PCI-e cable using lower AWG cables than the ones shown in your picture/


220v AC is much more efficient at shifting wattage than 110v AC; watts=amps*volts so you're looking at half the amps on a 220v circuit compared to 110v.

Approx 2kW per Neptune divide by 220v = 9A per Neptune

40A breaker would be cutting it a bit fine for 4xNeppy so a 60A breaker (or 2x30A/4x15A) @ 220v would give you a nice factor of safety around 50%.

u27

EDIT:
No problem; also you said 120v so you might be looking at 240v... doesn't make much difference.

I managed to get the advanced page; I think you have to initiate it by clicking that tab but it never wants to load the first time after restart. So to get advanced tab just flick to it and then to something else before going back to advanced tab.


Yes, 0A and 0v for those two DC/DC.


I can't even get that one running at 50Mhz.


Thanks for the tip, but no joy.


2.9... KnC still haven't delivered a 3TH machine or a refund.


What is safe voltage to increase to?

u27

Thanks for the insight bud; I sure did.

Plus they will have gone home for the weekend now.

The other three dies on that cube work for the most part so I think cable issues are unlikely to be the cause; I have tried swapping that cube with another one i.e. different PCI-e cable, different PSU, different ribbon, different beagle socket/

I managed to get the firmware uploaded; must have tried 8 or 9 times that timed out and then it worked for no apparent reason. Now I have no advanced tab and additional errors:

It just times out after a while/

Same from different browsers and different devices.

2nd die on first chip has not worked at any point; totally screwed I think.