Avalon 741 Voltage Offset | Bitcointalksearch.org

lrowland21093

member

Activity: 85

Merit: 16

As a home miner, I am balancing those sound and power against heat and noise.
I set all my 741s to -2 because it makes so little difference to the actual TH but it makes a HUGE difference in the power utilization and the sound. I loose about 1TH by setting it to -2 versus 0.
The power is 150W less at -1 and the noise goes from just about 59dB to high 40's (at 3 feet). This is a huge difference in a home environment.

(Sure, if I had a data center, a dedicated soundproof room, or even a wife that did not care, I'd have a bunch of craptastic S9s whining away and my Avalons would be running at +1.)

With four 741s at home the -2 makes life much better and the wife approval factor is much better. (At least it was until BTC went below 9K! -- "No really, honey, it will go back up - way up!"

)

CryptoHodler30

jr. member

Activity: 112

Merit: 6

Okay sounds good. Even at +0 right now it's running at 28c/86c. But I will turn it down to -1. I want to to last but thought since it's been so cold it would be okay to run it at +0 or even +1 for a little while just wanted to make sure the 1200 how server PSU could handle it.

frodocooper

sr. member

Activity: 351

Merit: 410

I'd keep the A741 at a voltage offset of -1, and not run it beyond a voltage offset of 0.

Here's why:

Quote from: lightfoot on November 06, 2017, 11:26:36 PM

General information:

This is information that applies to pretty much any type of miner.

Keep the die temperatures on the hashing engines below 45c for best results. As dies get hotter they draw a lot more current as they hash faster, it's not a 1-1 relationship. Likewise as they get hotter the chances a die will short increase exponentionally. So run it a bit slower, and life will be longer. Run super fast and be sure to budget in repairs.

...

Try to keep DC-DC temperatures below 80c or so. Going much about 90c on a DC-DC will cause the current loss in the supply to go way up, which means heat which means greater chances of a FET shorting which results in the usual fireworks.
If you're using a really big power supply to power a bunch of miners, make sure to wire in a good fuse on each miner power supply line. The reason for this is as follows: A 4,000 watt power supply can put out 333.33+ amps of current into a direct short before the supply will crowbar (shut down). If you're feeding miners using 16 gauge wire (30 amps max) and the miner shorts internally you will have the force of a pair of clothes dryers focused in an area about an inch or so square. This *will* cause wires to melt, insulation to catch fire, and miners to burst into flames.
Make sure the power supply you buy is big enough and good enough quality to handle the miners you run on it. Don't spend thousands on a miner, then try to cheap out with a $30 power supply. A cheap power supply will cause all sorts of weird problems, from random crashing to melted connectors (due to the wiring being too small), to burned connectors to a miner running at lower speeds than expected. Check the voltage of the supply at the miner while it is running, if voltage is below 12v (11.5 is a bit low, 10 would be seriously bad) upgrade the supply. Everyone has their favorites, I like the Corsairs without the modular plugs.
Check to see if your power supply has multiple rails. If so don't plug two different rails into a single side/board/blade of a miner. Doing so can cause odd problems. Normally all PCIe plugs on a single card are connected together inside the board; you want to ensure that each board has its own rail powering it.

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CryptoHodler30

jr. member

Activity: 112

Merit: 6

So do you know how many watts is needed to run at +1. I have the 1200 hp server PSU with 14awg power cable. I don't know the size of the pcie cables. Running on 240 service.

Running at 0 offset no wires are warm/hot. I think all the cables are good but I don't know if the hp server PSU can handle +1 offset

itzazkrit

jr. member

Activity: 51

Merit: 2

Voltage offset is under CGminer configuration tab when you log into controller. "0" is default. -1, -2 are less power, +1 more power. I was running -2 at average 6.9TH/s, -1 @ 7.1, 0 ~ 7.2, +1, not sure. When I cranked it up, I blew my china power supply. Currently working on dual HP 750W setup. Waiting on parts. Generally, lower power will result in lower overall temps, and longer life on parts (less strain on miner and power supply). However, I only saw a few C diff between -2 and 0 settings. So will really just be what your power supply can handle. If it is robust with good wires, crimps, terminals, etc, then you should be able to go to +1 to get most hashpower. When you change settings, I would wait a few hours to see what average is to really gauge the effect. Cheers!

Itza

CryptoHodler30

jr. member

Activity: 112

Merit: 6

Hey guys

can you tell me about how to set the voltage offset for the avalon 741 or point me where i can read more about it. I am currently running on 240v service and a 1200 HP server PSU. I have put it at -1 but what does that do? Also how does it affect power and TH/s?

Topic: Avalon 741 Voltage Offset (Read 295 times)