Well, I got this excelent monitor paired with 2 GTX 780. The thing is, before getting my second gtx, I was using the 144 hz with no problem at all, but after adding the second gpu and activating sli, the monitor, at any frequency above 60 hz starts "blinking", some kind of interference that takes kind of half of a second, not the entire screen but some lines, it's not continous, but like 3 secs, and then 2 minutes later again... pretty annoying tbh.
Tried updating drivers, swapping the dual link from one card to another, changing cable but this mot*** fuc*** problem persist. It doesn't seem to be the monitor, since it actually works at 144 pretty well when sli is disabled. I don't know about the video cards, because when it comes to performance they just rock.
@edit: btw, while playing it doesn't blink at all, but i've noticed colour shading when moving, and then when i focus something it goes normal, although it doesn't happen all the time. Main issue is when im doing desktop stuff.
I have heard that the cards do not like 144Hz, you said anything above 60, but did you try locking the monitor at 120Hz? That has fixed the problem for some people. Other than that did you try the second card by itself to see if there is a problem with the card?
I just mean setting your monitor to a refresh rate of 120hz. So you do not see the lines/blinking when either of the card is just running independently at 144hz with SLI turned off? Yeah I love the mobo too!