I recently got a 2nd GTX 770 for my old i5-2500K PC and I tested that both GPUs work individually but when I put them together in the same system and enable SLI the Nvidia driver crashes and restarts every time I try to launch anything GPU-demanding like a game or benchmark. It works fine on the desktop using DisplayPort at 1440p 120Hz though.
Oddly enough SLI works when I use an HDMI cable, but using HDMI I only get 1440p 60hz whereas with DisplayPort I should be able to get 120Hz (it seems like I cant get 144/165Hz using the 770)
It even crashes when I have the monitor connected over DisplayPort set to 60Hz and disable Gsync and DSR.
It's not a HUGE deal since this system will most likely only be connected to 1080p displays over DVI or HDMI and my 1440p 165Hz Dell S2417DG will mostly be connected to my GTX 1080 system but I'd still like to figure out this issue if possible.

Anyone know whats going on?
Thanks,
S2kG