NVIDIA drivers won't start when I try multimonitor with AMD

[Gron113]

I have a GTX 1070 STRIX, and I dug out the R9 270 from my old system to try and run a second display, instead of the Intel HD. So far the AMD card is going swimmingly, in fact I am typing this on the second monitor through the AMD card, but now there is a conflict with the 1070 - it doesn't send anything to the main monitor, and when I try and run GeForce Experience or something like that it says I have no NVIDIA card in my PC.

I AM ONLY using the AMD card to run the second monitor for youtube videos and the like, I am not trying to make both run the same game.

 

[The_Staplergun]

Ill be honest you're much better off running a single card. It's a bit of a miracle you got two different brand cards working.

 

[Gron113]

Well, 'working', I'm posting this after I deconstructed the whole thing - kept getting a "video_tdr_failure" bluescreen, or just a complete freeze, about 15 seconds after my PC went into windows. I don't know if it's a power issue - because I only have a 650w PSU, or a driver issue - because the error doesn't happen in safe mode (only on one monitor) or BIOS (same).
TLDR Doesn't work. Any way around the bluescreen though?

 

[The_Staplergun]

It's not power. That's enough for it.

I'd attribute it to a driver error. It has to hand off rendering when transferring windows across the screen border. Each card renders what's in its own display. If you pass any object between the two displays, it glitches as one card attempts to render part and the other card renders some.
It can go so far as to cause crashing.