Hi everyone,
seems as if it is a good recommendation to run GpuGrid only on rigs with Windows XP X64 installed and the system environment variable Swan_Sync set to 0.
All of a sudden, my FERMI GTX 480 has really picked up the pace. But I don't know what the reason could be or why it didn't run like that under Linux X64.
The reason why crunching here with Win7 X64 is really bad could be the WDDM overhead as one can read here in the other boards.
Perhaps under Linux a new driver generation can bring much better performance although with all three OSs I used the newest drivers available.

Cheers everyone,
CH