2D optimization with Quadro4 900 XGL

Got an aircraft simulator type app ( displays and control panels, no out the winder ) which we have ambitions of running on some new Dell 320 Workstations ( 1.8G ).
VC is a Quadro4 900 XGL.
The app is a 2D no texture anti-aliased set of loosely coupled binaries most of which run a single window on one or other of the dual heads we have ( 20" NEC LCDs ).

We had been hoping to be able to get a refresh rate of 10Hz on the app but that doesn’t look like its going to happen

We have another benchmark type program that will run 85 Hz flat out on our previous platform ( 1.6G w/Wildcat II 5110 ).
The benchmark app is structured more or less identically to a subset of the full-up app.

We’ve diddled with settings until we are blue in the face but we are taking a 25% performance hit ( refresh rate ) on the new machines.

Given the reputed performance of the Q4 we are a little surprised at this and yeah I know this is kind of a nebulous description of the problem but I was wondering if there was anybody out there in the same boat.