Re: Fedora 12 + multiple video cards + Xinerama + vga_arbitor is unusable
195.36.31 and 256.35 are both pre-patched, and should avoid this interaction with the VGA arbiter. If you are trying these versions, and still experiencing problems, you may be affected by another bug. Please start a new post and include an nvidia-bug-report.log.
To be clear, the patch to the driver does not patch the VGA arbiter. The VGA arbiter is part of the kernel and it currently behaves in a way that can break certain multi-GPU setups. We're working with the kernel VGA arbiter developers to fix this in the kernel; in the meantime, the patch to the driver works around the VGA arbiter's broken behavior.