This works for me so let me know if it works for you, I got a GTX 280 used the method on 32bit and 64bit vista........I have no idea on any negative effects so dont blame me!
Step 1 Rivatuner
1. Install Rivatuner, under power user tab>Rivatuner\NVIDIA\Overclocking - EnablePerfLevelForcing...
Is anyone still interested in a solution for the clocking problem? i solved it, 2d clocks when u want, 3d clocks when you want etc.....this works for 32bit and 64bit windows. I figured out a way to have it forced to watever you want....and i have 2 monitors. Been forcing 2d mode when i want it...