Topic: Your big@ss Hash Rate might actually be hurting you (Read 1446 times)
Thanks for the interesting info! I had no idea that large hash rates could actually result in less stable share counts if using overclocking. very enlightening.
I've noticed this too, and completely agree that you have to fine tune for shares/hour rather than hash rate. You have to be careful, though, about measuring the shares/hour due to variance. It would be nice if there were some standard and accurate way of doing this so people could have pissing contests in terms of shares/hour rather than Mh/s.
It can also randomly fail and generate nothing but bad hashes too. I had mine running on the edge until I woke up the next morning and had -300 or so shares lol.
That's why I do not overclock to the point where I need to increase the voltage. I would only get a few percent higher hashrate (assuming hashrate scales linearly with the GPU MHz) but more heat and power consumption. 1GHz (~310MH/s) IMO is enough for a 6870.
The time to calculate a share can vary, just like the time to calculate a block (assuming constant difficulty). It is interesting though, I'll try to calculate my shares/hour.
The time to calculate a share can vary, just like the time to calculate a block (assuming constant difficulty). It is interesting though, I'll try to calculate my shares/hour.
that's why i test all my overclocked cards for graphical errors
if there is the slightest issue i clock it down to prevent invalid shares and possible freezes
if there is the slightest issue i clock it down to prevent invalid shares and possible freezes
i have noticed ppl that overclock "to extreme" often create a lot os "stale" or "invalid" shares. dropping a few Mhz can improve your accepted share and lower stale share rates thus giving a better return 
hope thats a help
hope thats a help
My problem was never excessive Stales/Invalids.... it simply took a long time to produce anything (other than heat....lol).
Unfortunately, I have peaked as high as 5% Stales at times, but this is uncommon for the most part. I still see the odd stale share, same as always.
This 'tuning' has not affected Stales for the good or bad.
How long of a period are you taking to get shares/hour? It can vary.
I used 2 different pools with LONG rounds and monitored each for 3 hours on 2 seperate occasions/rounds.**I should clarify though**
I run 3 cards (all 6870's) in the test machine in question, with the lowest card starting approx 260+ and the top card of the 3 doing 290+ Shares/hour during the testing/monitoring, using the most basic OpenCL setup in Guiminer with "-v -w128 -f1".
The same card was not always the highest producer, the 3 cards all maintained 260+ and each would peak at over 290/hour for periods of 30mins or more before leveling off to 280-ish.
Prior to this, clocking the cards as high as I could get them stable, producing nearly 315Mhash/s each.....they would never peak over 250 shares/hour.
i have noticed ppl that overclock "to extreme" often create a lot os "stale" or "invalid" shares. dropping a few Mhz can improve your accepted share and lower stale share rates thus giving a better return
hope thats a help
hope thats a help
How long of a period are you taking to get shares/hour? It can vary.
This really only applies to those who overclock their video cards.
I realize that every discussion around here has to do with how high people can tune their HASH RATES to.......
BUT, has anyone ever paid attention to their SHARES/HOUR ?
Recently I have been using my average SHARES/HOUR in Guiminer as a 'fine-tuning' tool of sorts and have achieved measurable results.
The math speaks for itself.
By simply turning down the overclock by 1 or 2 Mhz, I can increase my SHARES/HOUR on a single card by about 50 to 70 extra SHARES/HOUR...and able to maintain it.
(HD 6870 @ 302MH/s, 980 MHz GPU/Mem, 1280mV, 290+ SHARES/HOUR in Guiminer).
I have tried to counter this by adding more Voltage to the card, but only saw more heat generated and not more shares.
The 1-2 MHz drop in clock speeds was enough to increase output and not affect overall HASH RATES by too much. The trade-off is more than worth it.
Are you 'riding the ragged edge' with your overclock ? time to re-evaluate things. Save heat, card life and increase output.
Post#2 for me....
I'll shut up now..lol
Cheers,
Allan.
---------------------------------------
Did it help ?
Feel free to send something my way - 1QGjSCJ1tcz1kXnqB4KPqcY8kZz2Guwbef
I realize that every discussion around here has to do with how high people can tune their HASH RATES to.......
BUT, has anyone ever paid attention to their SHARES/HOUR ?
Recently I have been using my average SHARES/HOUR in Guiminer as a 'fine-tuning' tool of sorts and have achieved measurable results.
The math speaks for itself.
By simply turning down the overclock by 1 or 2 Mhz, I can increase my SHARES/HOUR on a single card by about 50 to 70 extra SHARES/HOUR...and able to maintain it.
(HD 6870 @ 302MH/s, 980 MHz GPU/Mem, 1280mV, 290+ SHARES/HOUR in Guiminer).
I have tried to counter this by adding more Voltage to the card, but only saw more heat generated and not more shares.
The 1-2 MHz drop in clock speeds was enough to increase output and not affect overall HASH RATES by too much. The trade-off is more than worth it.
Are you 'riding the ragged edge' with your overclock ? time to re-evaluate things. Save heat, card life and increase output.
Post#2 for me....
I'll shut up now..lol
Cheers,
Allan.
---------------------------------------
Did it help ?
Feel free to send something my way - 1QGjSCJ1tcz1kXnqB4KPqcY8kZz2Guwbef
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