I have a pretty dumb question about Crossfiring/SLI-ing a GeForce 760 and a R9 390 DCII together.

[Lt Mashumaro]

Like it says in the title, it's a pretty stupid question and I'm fairly certain that I already know the answer to it. My brother, who I consider more knowledgeable about computer hardware and who is giving me the R9 390, insists that I can use my GTX 760 alongside the R9 one. I know that he mines cryptocurrencies, and I know that's what he was referring to in terms of using them side-by-side, but I don't really mess with mining. I use my computer primarily for gaming. What I'm concerned about is the fact that they're two different chipsets, require two sets of drivers, and the AMD R9 is lightyears ahead of my GTX 760. Wouldn't those drivers conflict with each other? My board is an AMD board that isn't one of the ones that can SLI two Nvidia cards, and I'm concerned about the space on my board anyway because I read the reviews on my Gigabyte 970a-DS3P that the PCIe x16 are cramped together and it would be difficult to fit two cards comfortably on that board.
So what it all boils down to, can I, like he said, use them together if I'm lucky enough that they'll both fit on my board?

Also, a bit related but not really, if I'm unable to use the aforementioned cards together, I was planning on letting my fiance use my GTX 760 with his 750 Ti if they were able to SLI. Again, two different cards, but I assume that they're similar enough that they might work? I dunno, I'll let you experts tell me.

 

[SkyNetRising]

Just use R9 390. Make sure your PSU is capable of supporting it.
You could use GTX 760 as dedicated physics card. But I find there to be a little or no benefit in doing so.

SLI works on identical cards only, cards must support SLI and motherboard must support SLI. If any part of this is not satisfied, then SLI is not available.

GTX 750ti doesn't support SLI at all.

 

[Lt Mashumaro]

Just use R9 390. Make sure your PSU is capable of supporting it.
You could use GTX 760 as dedicated physics card. But I find there to be a little or no benefit in doing so.

SLI works on identical cards only, cards must support SLI and motherboard must support SLI. If any part of this is not satisfied, then SLI is not available.

GTX 750ti doesn't support SLI at all.

Yep, you just confirmed my doubts. Thanks. I planned on just using the R9 by itself anyway, but my brother insisted I could use both of them at the same time. Just wanted to check with some people who would be more knowledgeable about these sorts of things. He's also giving me a 850w power supply and 8gbx2 DDR3 RAM along with the new card, so I'm sure the power supply will be ample enough to handle all this new hardware.
Also it sucks that the 750 Ti won't support crossfire. I guess I'll just keep the 760 as backup. I'll definitely miss Shadowplay though.