Z9 performance and general discussion


#285

people, what do you think, can I use a PC power supply at least 800W, which has 6x PCI-E connectors and connect them to two Z9mini and use an adapter from molex to PCI-E for the boards on top?
maybe someone is already doing like that?!


#286

I have basically the same question in that I want to power two z9 minis with one PSU. I don’t know how much power the control board on top draws, and I haven’t found an answer to that.

I’m in a slightly different situation, though. I have a 1000W EVGA G2 PSU which has 6 VGA connectors. The PSU came with 4x 8(6+2) pin and 2x 6 + 8(6+2) pin cables. In short, it means that I have a total of eight 6-pin connectors distributed between six VGA cables. However, I do not know whether it is safe to power both a hash card and a controller board on a single cable (the cable with two connectors). These are original cables provided with the PSU, and I somehow doubt that EVGA would supply such cables if they were unsafe.

Theoretically, a batch 2 unit, overclocked to 650M@400W would need 100W per connector (if power is evenly distributed). It is reasonable to think that the controller board draws less power than a hash card. If the dual cable is connected to one hash card and the control card, the wattage of this cable should not surpass 200W.

@Uche32: There has been stories of melted molex-to 6-pin-adapters in GPU mining, so gather some credible answers before proceeding. I have no more electrical knowledge than I got from high school and Google, so I can’t help you with your question. However, using an 800W PSU for two z9 minis seems to be pushing it. If an overclocked unit runs at roughly 400W, you could end up short of power. You might be better off running the units at stock speed, or at best just a slight overclock.


#287

Answer 1:
You need around 30.4-33 amps for your overclocked Z9 mini.
The controller is about 1A of that, sometimes it is less sometimes is spikes up a bit. But 1A is a good average to use.
I would not use a sinlge 800w psu for two ASICs that could draw 800w. Peak efficiency is usually achieved between 40-80% capacity. Pick the supply with the best peak efficiency where you will be using it, for the cost/time frame you expect it to last. This is mining, not gaming. The numbers matter in the long run.

Answer 2:
Don’t think of it in terms of watts. Look up the ampacity per pin of the connector, wire guage, for the length of cable. The standard 6 pin PCIE aux power cable has only two current carrying pins each for +12V and GND return. The asics input is 3 and 3 per board. Your limitation might be your PSU connector.

In general though, you already don’t have enough connections. You should also check if it is 1000W on a single 12V rail or multiple rails. You will need to manually balance the distribution with your cable scheme if they are multiple.


#288

Specific note on efficiency:
There are plenty of cheap supplies out there that have great peak mid-band efficiency but do not have an “80 Plus” badge. The ratings that the 80 Plus corp sells you the rights to put on your product just guarantee that a sample passed the curve. The platinum and titanium curves have requirements at low loads that in general make supplies more expensive. You don’t care about that. Focus on efficiency at your load amount. So yeah, look for 650-800w with great middle peaks. You just have to do a little research to find them. The input to the mini is regulated down to like .9v, so don’t worry too much about noise+ripple. If it meets ATX specs it’s fine.


#289

Yes, exactly the power cycle/shut down concerned me as it’s normal here that power stops for some seconds every 2 or 3 days, restarting most asics.

An additionally advantage i found with the generate/use archive that once i have done it on each Z9 mini i have the archives/backups for each anyway. So once or some day it’s needed to make a full reset i have everything ready including all other settings like network, stratums, fans, whatever…


#290

I have tried some things so far.

  • Tried a Baikal X10 on a PC 650 power supply, while the Baikal should use at most 400-450W that PSU got really hot and i replaced it after 2 weeks just to be sure.

  • With my E3 i used a 850W PC power supply. I needed 1 connecter more than the available ones and used a splitter for 1 cable. That cable/connector has blown, seems it was too much power for the slitter cable…

  • Right now i use 1x Bitmain PSU for 2 Z9 minis, perfect, no problems.

I think it doesn’t make sense to use PC supplies. The price for a Bitmain or similar PSU is about USD 100 and you can connect 2 Z9 minis with it, makes average about USD 50 for PSU per asic. Pretty sure it’s the best solution, enough noise isn’t the issue.


#291

the archive is perfectly editable, making it dead easy to play around with frequencies.

just edit the cgminer.conf and done


#292

If you want options I’m using a few 1400W PSU from https://parallelminer.com I have 3 z9m plugged into each. These can run at 100% haven’t had issues with these.


#293

looks like a winner to me.


#294

What’s the point of a 30-day warranty!?:rofl::rofl::rofl:


#295

Thanks for the answers. But to clarify, if the control board only draws 1A@12V (source?), it would be well within the SATA-specifications too (thinking about using a SATA to 6-pin adapter). As I understand it, SATA is rated at 4.5A x 12V = 54W, which should be ok…?

For myself, that would leave 6x VGA connectors that I connect to the hash boards, each with its own cable. I could buy another industrial PSU, but I have the 1000W just lying around doing nothing right now. The specs on the PSU states that it has a single 12V rail of 83.3A which would be ~1000W.


#296

I don’t think the control board uses anywhere near the power for that to be concern. If I read this right you want to go from an 8pin to 2x 6pin right? one to the control board and one to a hashing board. I think you can get away with that. I believe 8pin from EVGA is rated for 300W.


#297

You’re right! I wasn’t thinking about adaptors. You should be fine with that configuration then :smiley:


#298

DOA on used merch.
But at some point the return shipping costs more than the product haha.


#299

the mini price dropped a bit
probably those are only able to run at 450MHZ LOL


#300

My batch one will run fine up to 800, but doesn’t improve hashrate much, lots of errors. I run it at 731.

My two batch twos are running stably at 700 and 675. The second wont run at 700 long before a crash. The physical boards look the same, and the power consumption for me is the same per board at a given frequency. I took one new board out and inspected it relative to my pictures of my batch one board. I don’t think they changed anything in hardware.


#301

@Kahooli, thanks for taking the time to give us input on this. To summarize, the three configuration options I’ve been thinking about to power 2x z9 minis is:

  1. 6x VGA cables to each 6-pin hashboard + 2x SATA cable to 6-pin adapter to control boards
  2. 6x VGA cables to each 6-pin hashboard + 2x extra 6-pin connectors (on two of the VGA cables) to control boards (@amanalar this option was the first I posted. Then on each ASIC, there will be one VGA cable powering both a hashboard and the control board)
  3. 6x VGA cable to each 6-pin hashboard + 2x separate Molex cable to 6-pin adapter to control boards

If option 2 is viable and within safe limits, I’ll go with this. Both no 1 and 3 requires use of adapters, and could potentially be a weak link. But if the control board only draws like 1A, I doubt it will catch on fire.


#302

Option 2 has also adapters so they have the same possible weak link or do I understand you wrong?


#303

Option two is the simplest. Again, even at 731MHz each board is only 8.3A + .5-1.0 for the controller.


#304

No adapters in option 2. The PSU come with 4x regular VGA-to-6-pin cables and 2x VGA cables that have dual connectors on the other end, 1x 6-pin and 1x 8 (6+2)-pin (see embedded picture). Which means that I can connect one of these cables to two 6-pin connectors while at the same time use only one of the six VGA connectors on the PSU.