Well, now that I have my GF4 TI4600 and was immediately disappointed in the performance...I went to tweaking and researching. (I have post somewhere else in here on this as well). From what I have been able to find, the 28.32 det drivers have a bad reputation. I've seen more people complain about them than I have people that like them. With the 28.32 drivers, I was getting random lockups and general video quirkiness. Sooo, someone said "get the 29.42's".....so I went looking. Oddly, these drivers have not been released yet (even though there is a windows certified version). I found them available on a Russian website and downloaded them. I'm here to say, they work far better than the 28.32's did on my system. Since installation, I have upped my frame rates quite a bit and have not had one single lockup or any other video related weirdness.
You can find them here:
http://www.3dnews.ru/download/drivers/nvidia/(the site is in Russian, but it isn't hard to find them ...the download link is on the far rigth side)