Re: Which pixel clock rates are available ?
Yes, have looked through Appendix L. I believe my mode lines are OK since they were generated by "videogen" and pass it's NVidia check - and also the X-Server seems to accept them. Unfortunately, the DVI cable rate (<= 162 MHZ) is much more limiting than either the DAC limited rate on the video card or the max bandwidth limit on the monitor.
So from your response, it sounds like a SHOULD be able to "demand" a pixel clock rate of 156.92 rather than 162 MHz from my video card. I'm assuming that my monitor IS correctly reporting the pixel clock that it is seeing - because it does see/report a different pixel rate when the video card is displaying the boot console through the video BIOS (also at 1600x1200). Short of finding a high bandwidth oscilliscope, I don't know how else to confirm the true pixel clock rate.
Unless someone else is aware of another limit on the available DVI pixel clock rates, sounds like I might need to file a bug report ...
Thanks for the reply - Scott.