I have pulled my hair out over the last week over 7970s.
See last post here:https://bitcointalk.org/index.php?topic=117221.520
Taco can you take a look at my problem quoted below?
Okay - need some help on this anomaly.
First rig - Sapphire 7970 standard edition with Vapor X, used settings suggested in Taco's thread - out of the box 650k/H per second.
Second rig - two (2x) Sapphire 7970 "GHZ Editions", used exact same settings in Taco's thread - out of the box - only about 350 k/H per second.
I have spent the last week in "newbie purgatory" so have been unable to discuss this issue. Finally on the second rig, I was able to get 500k/H per second/card by putting aggression back to 13, and overclocking the memory to 1680Mhz.
Can anyone tell me WHY do two of the same brand/manufacturer, same model, have such huge variance in performance?
Why would the two "Ghz editions" VASTLY under-perform the standard one?
Does anyone have any suggestions experience with a Sapphire "GHZ Edition" that could explain the variance? The standard one was plug and play @ 650k. The better ones have taken a week of tweaking to even reach 500k/H, and NONE of the recommended settings worked. I know it is not bad cards because they both perform the same - what is different about the "GHZ editions" that is hurting them so much, and made them so finicky?
First rig is Q6600 65nm, 4GB DDR2, PCI-E 2.0, Win7 Pro 64, Sapphire 7970 - 650kH/s
Second rig is 22nm Quad i5 Ivy Bridge, 8GB DDR3, PCI-E 3.0, Win7 Pro 64, 2 x Sapphire 7970 "GHZ Editions" - 990kH/s (both cards)
I followed all instructions in this thread. The second rig would only do about 300 per card until I overclocked the RAM on both cards to 1700Mhz and dialed back aggression to 13. Any variance from that setting and I get LESS than 500kH per card.
I would REALLY like to get the potential out of these supposedly "better" Sapphire 7970 Ghz editions.