With cooling season approaching, I need to increase the efficiency of my S3+s or turn them off. I've seen sporadic discussions on best firmware to upgrade to, how to undervoltage, etc., with differing results.
Is there a thread on increasing S3+ efficiency and a "proven best" method out here?
It's not hard to test yourself with a watt meter at the wall. For every frequency wait until the fans are at the normal rate, then record the wattage at the wall and the work utility number on the miner. A simple calculation will show you what frequency provides the best use of watts to hashes. Doing it yourself also will account for the difference your power supply makes.
My best option was to vent things outside directly. Problem solved for me, and still overclocked.
My numbers currently:
OC'd at 250, WU 7,021, 399 watts. So 17.6 WU per watt consumed.
I'm an electrical engineer and have a spread sheet of measurements to determine J/GH at the wall. Looking at my last bill and with my electricity cost at 0.13/kWh and the current BTC value, I'm just breaking even or making a small profit when I factored in the reduced heating cost during the winter. Simply changing the frequency won't make a significant difference. Was hoping to change freq and also undervolt but read mixed results on that also based on firmware and other issues. I had great success using the HB-lead method to keep my S1s profitable for a long time. I haven't been back here for a while and I was hoping someone had an S3 solution.
I shut down my miners and wonder about the future of BTC when more people do the same. I know if enough do, difficulty will decrease, ...
If what you say is true, I'm wondering why people under-clock if performance per watt does not increase. So I had to test 200mhz with my own eyes.
To review, OC'd at 250, WU 7,021, 399 watts. So 17.6 WU per watt consumed. That's putting out an average of 505GH/s.
Underclocked at 200, WU 5680, 305 watts. That's 18.2 WU per watt consumed. Putting out about 406GH/s
So sure it's a little better, you save about one old bright hot incandescent light bulb from being on 24 hours a day, for a loss of about 100GH/s. That could make the difference in some people's power costs. Some people with lots of things plugged in or lights on might be able to save 100 watts from being used daily.
I didn't say performance per watt, or efficiency in terms of energy/hash (J/Gh) or in terms of power/hash rate (W/Gh/s) doesn't increase from underclocking (or changing the frequency). I just said it's not significant, which you confirm in your numbers above. That's why I was more interested in whether anyone had a proven technique for under
voltage, or lowering the voltage to each chip. I did this with my S1s last year and ended up reducing the J/Gh number on each by about 1/3, meaning I was getting the same hash for about 33% less energy. That is a significant efficiency improvement. On the S1s, I changed the voltage by using an HB lead pencil trace to reduce the resistance in a voltage divider circuit for each chip that led to a lower chip operating voltage. I read that you can
undervolt the S3 chips much easier through a firmware switch on some of the firmware updates. But have read mixed reviews and was wondering if anyone had succeeded in making a significant efficiency jump using that technique.
