Found this
"Divide and Conquer The Mac Pro includes software that dynamically manages the way the PCIe interface divvies up its bandwidth. So if you add new graphics cardssay, multiple GeForce 7300 GT cards to drive additional monitorsthe Mac Pro will automatically sense them and allocate its PCIe bandwidth accordingly. Itll even check with you to make sure its set up optimally for what youll be doing."
So my questions are, am I reading this properly will 2 cards dispense the workload there by increasing GPU power and allocating it to FCP etc?
and does this allocation work in the older MacPro dual cores?
Wouldn't this solve the power issue, with a increased heat problem?