You shouldnt get more than 340 mhash on a 5970 core @ 725 MHz, even with perfect ram speeds and miner/kernel options. If you're spiking 350-370, definately something awry going on there. Is your GPU activity maintaining 99+%? Doing nothing on the computer running on the miner? I'm running 5830, 5870, 5870, 5970, and 5970 and I get sudden dips of GPU activity (40-70%) if I do ANYTHING on it, and it kind of cascades between the 7 GPU's for about 30 seconds before stabilizing and getting back to 99.5+%
My GPU's maintain about 60-75% activity. And yes, its a dedicated mining-server at the momemt, so I'm not doing anything else on it.
Tried only running one core again and then the activity goes up to around 96-98%. Strange..
What driver/SDK? Back with the old 100% bug if I ran both my cards on the same CPU, their hash rates would suffer.
As I wrote in the main post, 11.10 and SDK 2.1. When it comes to the CPU it maintains about a 50% load.
Ah I see that now. Must have glossed right over it.
Like ssateneth said, 50% of a dual core CPU is 100% on one core, and if you run both instances of Phoenix on the same core, the hash rates suffer. Upgrading to 11.12 will fix your problem.