Lol so let me ask you what monitor has 4k with more than 60htz.......It doesn't exist...until HDMI2.1 Displayport 1.4, there is no connection. The absolute only reason to run 2 1080tis is to ensure 60htz is over the minimum, but since you are apparently a computer expert you would no on a 4k monitor
What is this drivel??????
Depends on what you are playing and if you are moronic enough to pay 700$+ for an extra GPU that most likely won't be used will consume extra wattage and generate extra heat as well as cramp the airspace of the first card. Now with that said IF games you play that are DX11 have an SLI/Crossfire profile then that solves 1 problem, next is the simple fact that a single 1080 ti gets 40-60fps running 4k, sure the card will struggle in some cases but first off - THERE IS NO 4K MONITOR THAT HAS GREATER THAN 60htz REFRESH this is because of HDMI and display port bandwidth you apparently have zero clue as to what you are talking about a Titan XP uses HDMI 2.0b and DisplayPort 1.2, without reducing the overhead from color compression which basically leaves you with crappier standards.
What I am saying is there is ZERO reason for NVidia to create a GPU that exceeds the capabilities of the other hardware, it would be a waste of money over engineering a Die for it.
I honestly doubt you know as much as you think you do, If you understood how to build a system you would understand exactly what I am getting at, that's like NVidia making a GPU that can handle 120+fps for 8k on a single GPU even though the current monitor standards can only use 4k 60fps...................*****..seriously