Thanks for the reply.
NordicJedi
Technically, the 750 Ti should be able to run 3 monitors on its own. DVI, HDMI, DP. That might be the easiest solution.
That's how I'm running now. All three on one card.
The reason for using two cards would be to unload some of the graphics off one card. I often play older games on the machine, games limited to one monitor. As it is now I've scaled the graphics back to almost stick figure levels and the card runs at 100% load and 45 to 49C (I have the fans locked at 100%).
My thoughts were to put the left monitor on a single card, scale the graphics back up to decent levels while the other two monitors are used in the normal way. Surfing, email, youtube etc...
NordicJedi
Where was the second card missing? Device Manager, Nvidia Control Panel, etc.? Even if the cards cannot SLI, one card should not simply disappear after installing the drivers. Not sure what's going on with that.
Before installing the drivers I noticed that windows picked up on both cards. I did not look in device manager but the Hardware Wizard displayed two cards, two driver installs simultaneously. I cancelled this and downloaded the latest driver. After install I saw one card in Device manager and one card in Nvidia Control Panel.
I too was thinking that even if they can't do SLI, I should be able to run them together.
Since technically they should run together, I'll install the second card again and mess with it to see if I can get it to recognize. Like I said, there was no problem with my mining machine picking up all 6 of them and driving them to 99-100% doing mining. They functioned stellar in that role, even running 24/7 for weeks on end.