Re: nv driver used 75Hz, nvidia driver wants 76Hz!
No that does not work at all. I wouldn't expect it to unless there was a Modeline that was named exactly that, but I gave it a shot and my suspicions were proven true.
I also tried using this modeline:
# 2048x1536 @ 75Hz (VESA GTF) hsync: 120.2kHz
Modeline "2048x1536" 340.48 2048 2216 2440 2832 1536 1537 1540 1603 -hsync +vsync
However it does not work, and the monitor ends up at 76Hz with a kHz above 121 IIRC.