Hi guys,
First post here, and I'd like to contribute something about the XFX 7970's DD. A friend of mine and I have a rig running with 4 of them, and together they pull a steady 2.8+ Mhs. We accidentally broke on one of the cards (not by mining but by bumping into one of them :-)) and the three now pull 2.1+ Mhs. So; they're not shit.
But, it wasn't easy to get them at that hashrate. We tried a lot of different settings and it was hard to get them above 600 khs. Let me tell you what we did:
We've used the settings we found here:
https://litecointalk.org/index.php?topic=9844.0Then we still didn't get far above 600 khs. After a lot of trial and error, we noticed that it was TeamViewer causing the hashrates to drop by 80-100 khs per GPU.
So we finally found out that TV was the problem, and we are now mining for almost 72 hours continuously. There was one problem though; one GPU got above 90 degrees. We turned down the memclock to 1575 and the core to 1000 (from 1600 and 1044 respectively), and this GPU now runs at around 86 degrees. The other GPUs are in the 76-82 degrees range.
These high temperatures are the result of putting the rigs in a closed server rack (in a facility where we don't have to pay a lot for power consumption). When we were testing the rig at home in a living room, all 4 GPUs were steady in the 78-83 degree temperature range. So we're planning to move the rig outside the server rack.
So yes, these cards can be a bitch to get them at 700+ khs but they're not shit.
That's why I like them actually; because people get bad results you can easily buy them. They're not that expensive and you can get good hashrates.
Let me know if the settings in the link I've posted work and if you're interested in the config settings, pictures of the rig and/or our hardware setup.
