Re: NVS Quadro 450 poor performance.
The pixel clock shouldn't have an impact on rendering performance. I suspect this is not an issue with raw horsepower of the new card; software fallbacks are very expensive on chips newer than NV4x for various reasons, which affects the 450. Generally we try to accelerate all drawing operations, but there might be some cornercases that still cause us to fall back to software, introducing potential performance pitfalls on these newer cards. For this reason unless I can look at the exact sequence and combination of drawing calls, I can't really be of much help. The qtgears issue you're observing might or might not be related; I'll take a quick look at that to see if there's low hanging fruit there.
If putting together a test case isn't an option given the time constraints, can you provide NVIDIA with access to the full application?