Take them one by one:
- its older
-being a dual gpu means dat you are bound to software to run it cool and over 75% scalability
-just 4 gb for a dual GPU
- doesnt support 2180p ( not dat you really need it but stil...)
Now the gtx 780ti and titan.well this is how it works
TITAN =Gtx 780 WITH 6GB
TITAN BLACK =Gtx 780ti WITH 6GB.
The titans are like 6gb versions of this cards. The fact is dat there is no real world diference beteewn them at 3vs 6 gb.
After all it is said the gtx780ti is the best GPU from the pool.Also consider a r9 290x which are in the 500$ way cheaper but only 5% slower.
Again potato speaking. There are no games even at 4k that botlleneck the 780ti for its 3gb.
In every benchmark( and im spaking 4k) there is no diference beteewn gtx 780ti and titan black.
And 780ti for 1080p. You think you eyes can make a diference beteewn 60fps and 150fps and your some sort of mutant.
For 1080p gtx 760 or r9 270x its enough.
For 1440p the gtx770 and r9 280x are enough.
For 2180p the gtx780ti and r9 290x are enough.
Yes sure put gtx 780ti/r9 290x on 1440p for over-ultra setings but to put that card on 1080p is complete retardnesship. I mean unless maybe , and again i say maybe you have a 120/144hz monitor might be worth even though id chose a 4k display instead of that.