How to speed up Dual QUotro NVS 420 with Xinerama
We have a few Dell T3500 with 4GB of RAM, running RHEL 5.5. They have 2 Quatro NVS 420 installed in them, and each hooked up to 6 or 7 monitors. I have set up Xinerama so that we can have a big desktop, allowing user to move an application window from one to the other. Twinview is not used.
We are seeing extreme slowness, and high CPU usage by Xorg. On machines with only 1 Quatro connected to 4 monitors, also using Xinerama, performance is not an issue.
Is there any trick I should know about to speed up communication between the two cards? I understand there are also 2 GPU within a single Quatro. But now we are talking about GPU talking to each other over the PCIe bus. I am thinking there might be an issue there. Any hints would be appreciated.