I have a system with 4 FirePro W9100s. Each port (total of 24) is populated. If I launch an application with all of the monitors powered down except the one the main monitor is attached I get great frame rates. A simple example program we use with OpenGL will generate about 900 FPS. If I turn on a monitor hooked up to a different card the frame rate drops dramatically even though there is no rendering taking place on that card. With a single monitor powered up on each card my frame rate is only about 175 FPS. GPUZ indicates no activity on any of the cards except the one the main monitor is attached to. DirectX applications exhibit the same pattern. I have been working frantically trying to get the software that is distributing the graphics to the various ports to give me good frame rates but I find that the issue seems to be mostly in the system/hardware. What is going on that is causing the frame rate to drop when a monitor is turned on and is there anything that can be done to mitigate the issue?
EDIT: After a careful review of the tests I find that the issue seems to be specific to Prepar3D.