Quote from: drakoin on January 22, 2014, 03:18:44 PM

Quote from: Quacko on January 22, 2014, 07:59:47 AM

k, thx I'll check on of these days when I have the time again.
729 isn't very high though, my other 280x cards go @ 773kHs on stock voltages. I havent tried lowering the voltages yet, I probably can a bit.

Go for it, you will already save A LOT OF energy with undervolting only. If all this here inspires you to undervolt, that's brilliant already.

If you want to keep your 773khs, but still want to save at least some juice, then you can go for what I called "optimum (B)" in posting #28 = just undervolting, no sweet-spot-underclocking.

Quote from: Quacko on January 22, 2014, 07:59:47 AM

Here is my question though: As long as I make near 3x as much money with my mining than what I am spending on electricity,

Then you are a very lucky person.

Perhaps your government doesn't care about the environment so much, or it affords a massive army to secure low energy costs?

There is a huge difference between 0.12$ and 0.35$ per kWh.

Quote from: Quacko on January 22, 2014, 07:59:47 AM

I have to lower power consumption at least 30% for every 10% of hashing power I lose for underclocking and undervolting. Right? That sounds hard to do, that would mean that my powerconsumption needs to come down more than 100W, I find that hard to believe that it will...

Oh, just look at what we achieved here. I am down by 119Watts compared to the factory settings, 7970+7850.
Marcje speaks about now only 400 Watt from the wall, for two 7970! And before the same system was using 600Watts.

When I started, I was shocked how much money I lost on electricity, it was actually more than 40% of my total coinvalue. Since then, I have been sometimes more clever or lucky with more coins per day, but on average at the moment GPU mining is not very lucrative. Especially in countries which want to implement renewables, and take the whole population to pay for the transition.

Have a look at the principle that I am using in my thinking, and prove me wrong, please:

Kilowatthours (1kWh = 1000W running for 1hour, or 42W running for 24 hours ) are a way to speak about the total energy consumption, usually measured in Joule. Watt is Joule per second.

The hashing GAIN is per second (measured in coins per second), and the Joule LOSS is per second (measured in Watt).

So the calculation we need to do is

GAIN: The hashing GAIN per time (measured in average BTC that I make per month)
MINUS
LOSS: The wattpower, that is the energy per time that we use up to do it (measured on your monthly electricity bill)
GIVES the
PROFIT per time

Doesn't it?

But I agree, if you are in a country with cheap energy ...
OR if I am in those lucky days of very high profitability, e.g. during a coinstart ...

... then it makes sense to loosen all breaks, and just go fullpower into earning as much as possible per time.
Just forget about the electricity, on those days or in those countries, then ... the electricity costs (or pollution) are ... negligible.

Yeah, I know how to do the calculations, am an electronic engineer :p.
But just wanted to make sure if I missed something as I see you people putting that much effort in it while you might not actually gain anything if you don't lower your powerdraw by 30% for every 10% (but maybe my earnings are just very high). I pay about 24 eurocent per kWh here, that's $0.33 (Belgium, so not a large army hehe). Not cheap at all. But I do make about 3 times as much per day with mining than what I use in electricity. So, I am surely going to undervolt my cards, everything helps, but I doubt that for 10% lower hashrate that I can get to 30% lower power draw from the wall. I can check my overall powerdraw and spendings easy as I have a meter that allows me to put in the kWh price and it shows my total power consumption and total price, pretty easy!
Oh and my electricity supplier only supplies energy from 100% green (windmills, water, etc.) sources. So I am thinking about the environment, don't worry!

I just solved my problem too that I had with my powerdraw not going down even when I undervolted. Turns out I had a driver problem on my windows machine. I fixed it and now it's using less now that I have undervolted it. I am pretty sure I'll get as low as 1.05V for 1050MHz, which is pretty good I think.

The linux machine with the 2 cards that run at 773kH/s run at 1110MHz, so I probably wont be able to lower the voltages on those that much, but as you said it, every tiny bit helps, lowering the system power draw by only 50W would lower my energy bill more than 12 euro per month. Worth it!