GPU overheats or not enough power. Monitor temperature, add powertune +20.
That is not it.
![Sad](https://bitcointalk.org/Smileys/default/sad.gif)
I had this 290X running in my bedroom. It was very noisy, very hot, and produced 880 khash/sec.
Then I moved it to the basement. Now it is not noisy, it's not hot, and it produces 700 khash/sec. Tried 2 different computers.
The only difference is now the miner is running via remote desktop.I wonder if remote desktop limits graphics resources to the OS so one person cannot monopolize the system?
Anyone have any idea?