Can you run 2? Yes. In PCIE slots of x16, x8, x4(not recommended).
Is there a benefit? Yes, on the professional level - sorry, that's the best answer I can give because I'm not familiar with those programs.
I just know that some run multi-gpu Titan and Quadro setups for the kind of work they do.
-Heat produced; overall higher case thermals. The top card at the very least, should be a blower type(ideal for tight spaces). A standard fan model will thermal throttle due to proximity to the bottom card.
-Overall power consumed.
-A robust power supply is a must, don't even try to cheap out here, not that anyone ever should.
-Driver support is sorely lacking. So most times, you'll have one card sitting in your motherboard doing nothing. In some applications, the drivers are really half-assed, so the gains aren't as great as they could be.
-Requires a top notch cpu so your getting the most out of the multi-gpu setup - at least, for games.
Doesn't mean you CAN'T completely run multiple gpus in your rig, but yeah, it's pretty pointless for the reasons I already mentioned.
Certain 3D rendering programs can still take advantage without NVLink, but I'm not familiar with them.