This is certainly an interesting "feature," if you could call it that... I wonder if the info was ever going to be made public by NVIDIA without an incident such as this prompting them to divulge it...?

"The Overclocker Cafe ran into a fluke with the NVidia GeForce 6600 GT GPUs where in certain situations higher screen resolution equaled higher frame rates.  Not only were we stumped but so were the manufactures.  After a bug report circulated around NVidia for we did get an answer to the riddle.  The 6600 GT GPUs actually scale their settings back in some situations."