So I posted over there in the Nvidia Geforce forums about a GTX 660ti issue I'm having. I have two of them in my PC and when I had just finished fresh installing, both were detected but didn't seem to respond to SLI. My nVidia control panel didn't have the SLI option it usually does in the "Configure SLI, surround, physx etc." which is located right below "Manage 3d Settings" and above "Display". The cards were used from a previous build. I suppose I should mention right now I have the X470 Taichi (not Ultimate) and two EVGA Geforce GTX 660TI SC (https://www.techpowerup.com/gpudb/b767/evga-gtx-660-ti-...)
---Edit: Also, I'm currently rocking a gold rated Corsair 650W. It's brand new. Not sure if that's too low wattage to SLI - my last PSU was 1000w but it's bronze and six years old so reusing it isn't an option.
Because the cards were detected and not going into SLI properly, I went into the UEFI settings and tried modifying the 16x and two 8x options. Since that didn't seem to be working I switched to Gen 2 promonitory switch and immediately pulled up only black screens. At first I thought it had completely ruined my system. After a couple CMOS resets I eventually discovered that I just wasn't getting output to my monitors from my top card. When two cards are installed, I'm only getting output and detection of the bottom card. If only one card is in, I get detection and output from the top card (the 16x lane, the one closest to the processor). I've tried the original bridge from my previous build as well as the bridge that Asrock supplied when I received the motherboard.
16x vs 8x doesn't seem to do anything in terms of GPU detection and I'm a little hesitant to continue messing with the other two options (promonitory switch and whatever the other option is, I can fill that in in a second if need be. They're located all together in one of the bridge options in Advanced I believe)
I posted this in the nVidia Geforce forums and was only told that compatibility between Kepler and x2s seems to be in a bad spot right now. I wasn't supplied with much information in regards to that and attempted to research it with Google searches to no avail.