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Title: OC 7970 Post by: BTC guy on April 19, 2012, 01:43:29 AM I just got a few 7970 to play with. Im getting 640 hash but i cant get core stable past 1080. Cant drop memory below 900. And im not sure if CGminer or trixx is controlling memory and volts. When i adjust with trixx it shows changes within trixx but not within CGminer. Who here has already played with these and can give me some tips? I hear people talking 1150-1200 core and 700 hash. I would like to get that too if possible.
Title: Re: OC 7970 Post by: cmg5461 on April 19, 2012, 01:52:56 AM use afterburner.
Lowest I've gotten mine is .949v ~ 1000mhz w/ 710mhz memory ~ 580mhash/s Voltage won't change in cgminer. It's bugged. Use Gpu-z to verify the voltage. Also read the asic quality of your 7970's, as that will guide you with overclocking Title: Re: OC 7970 Post by: BTC guy on April 19, 2012, 01:56:25 AM Darn i thought i was done with these third party OC tools when i started using CGminer. Thanks for the tip will check out afterburner again.
Title: Re: OC 7970 Post by: BTC guy on April 19, 2012, 02:13:09 AM Now running 1125 core 670 hash. Gonna try for 700.
Title: Re: OC 7970 Post by: BTC guy on April 19, 2012, 05:02:17 AM Was running 1200 core 720 hash.
Title: Re: OC 7970 Post by: cyberhelix on April 19, 2012, 05:59:14 AM Now running 1125 core 670 hash. Gonna try for 700. I have seen 689 out of mine before... everything maxed out. (1125/1375) Good luck on the 700 :) DiabloMiner Rocks! Title: Re: OC 7970 Post by: phorensic on April 19, 2012, 07:47:18 AM Just like my 5830's I had a few hundred hours at top speed on my 7970 at a glorious 1200MHz core. Ran a few more weeks at 1175, now I'm down to 1150. It's the crashes in the middle of the night that I don't catch until I wake up that kills the profits. Which means it's better to run at a lower core that is more stable than try to eek out that last 5MH/s. As far as voltage, every time I cranked up voltage I had diminishing returns on clock speed while power usage and heat skyrocketed. I don't recommend touching the voltage.
Title: Re: OC 7970 Post by: BTC guy on April 19, 2012, 07:49:25 AM Your right. I just wanted to see what it could do. I have it running 1100 no volts. I might put a little extra volts for 1150.
Title: Re: OC 7970 Post by: AzN1337c0d3r on April 19, 2012, 11:08:46 PM The 7970 is incredibly efficient when undervolted but cranking up the voltage does almost nothing for clock speeds and power usage skyrockets. This is due a fundamental physics phenomenon which is related to the way we design transistors and the shrinkage of distance between source and drain called subthreshold leakage.
On a more practical note: My pair of 7970s can hit 1125 MHz at stock volts and generate about 1350 MHash/s. |