I got the cable today, and presto - it works. All Problems fixed:
1. No pink screen on changing refresh rate to 60hz - before I would get a pink screen when ever I used any refresh rate above 30 hz.
2. In the Nvidia control panel - 3 options of bit depth available now - 8,10, & 12. Before only 8 bpc options would show with hdmi - hdmi cable.
IMO for any nvidia GPU user which has a data port, it is essential - NO MANDATORY - to use data port 1.4 to hdmi cable. 8 feet cable on amazon is about Rs. 1700. Else you won't be able to use the full picture quality potential of the card - of-course this applies only when your display has HDMI inputs only.
Sad part is - how difficult is it for Nvidia to clearly state this? these cards are not cheap starting at 15,000k to 1.2lac. I was stumbling blindly in all searches and forums without any proper instructions.
I saw 2 or 3 other queries in Nvidia forums itself which talk about pink screen but no proper response to fix it, just states that set refresh to 24hz.
Same in MadVR forums.
Anyways thanks a lot, to all the FM's who contributed, now I will fine tune the MadVR settings.
Cheers,
Sid