Originally Posted by netllama
The nv X driver only supports one display per GPU. You should still be able to setup Xinerama across multiple GPUs to compare performance with the nvidia driver.
Seems like the nv driver doesn't support DVI either, but thats another story.
I set up three screens using VGA with xinerama and the 'nv' driver. Performance is better than the 'nvidia' driver with xinerama. In the case of a small java swing program I have written to demonstrate the problem, the nv driver with xinerama is vastly better than nvidia with xinerama. Performance with this program and nvidia + xinerama is terrible.
Perhaps it is time to submit a bug report with the test case unless there is anything else I can try ?