Quote from: proclivity on March 20, 2014, 03:17:33 AM

Reduce power 100W or more on your KnC miners

Hi all - I've read a lot about people increasing voltages to reduce errors and wake dies.. But how many of you have gone the other way and lowered voltages as much as possible while keeping errors low?

I have and I've reduced power by over 100W each of my November Jupiters using the 1.0 firmware. Here's a quick guide on what I did:

I'm going to assume you know how to use putty, can connect to the mining screen, and get around bfgminer settings.

As many have said, the first step is to change to bfgminer so you can see what's happening on each die. If you don't want to use bfgminer permanently that's fine, but you'll need it to tune so do this first and restart the miner if necessary.

Open the bfgminer screen and the advanced tab together. Then take a deep breath because you will probably freak out soon, but this is a very fast way to tune your miner. Read through the steps before you begin.

Make a note if your error %s by board. Reset stats in bfgminer. Adjust all voltages to -0.0803 and apply. This will make many of your dies start to throw errors and the screen will start to lite up with disabled core messages with a three digit code. The first digit is the board, 0 1 2 or 3 for a Jupiter, the next two are the core and this code also helps you determine which die. Here is the range from memory:
Die 1:aa-bv
Die 2:bw-dr
Die 3:ds-fn
Die 4:fo-hj

Check bfgminer error stats - for any boards throwing a lot of errors start looking for disabled die messages, I recommend going in sequence, if the first board is throwing errors look for disabled dies starting with 0. If you see:

0cn disabled

Then increase the voltage one step for board 1, die 2.

Keep watching the messages and try to find a core in each range. Don't spend too long, move on to the next board, repeating the process for all boards all core ranges.

Apply your changes and wait about 15 seconds for the firmware to cycle the cores.

Reset bfgminer stats. If you are lucky, and I was, one of your boards may already be stable. Repeat the process for any board that still has a high error rate. Only increase voltage one step at a time and only increase voltage when you see disabled core messages. Go through all boards all dies, apply, reset, repeat.

If you have any dies at -0.0803, lower these one step. Apply the settings, wait, reset stats, check errors. Reverse any that now throw errors, keep reducing any that are not producing errors.

Once you stop seeing disabled cores you may have a few dies that are still throwing errors. Now you want to switch bfgminer display to show all cores. Scroll through the list and look for ranges that have multiple cores throwing errors. Increase voltage one more step on these until you are happy with the error rate.

It took me about 10 minutes by the time I tuned my third Jupiter. All of my voltages are adjusted negative - most are around -0.05 to -0.07, I have a couple that went down to -0.09 and a couple that needed to come all the way back to -0.02. But, I've reduced both temps and power. I was getting many FAULT 4 messages regarding DC/DC temps but now they are all happy. Good luck and hope this helps you!

If KnC is nice maybe they will build auto monitoring and voltage trim right into the next firmware

if they are really nice maybe I will get a few extra Neptunes for saving them a few megawatts in their data center Wink

But how does this effect performance?
With ASICS we are still in the age of performance over power savings.