Dual Nvidias Win10 x64 error code 43, non functional


REMARK: Move the topic if placed incorrectly, pls.

Has ANYBODY in NVIDIA got an idea why cant be two nvidias installed in on desktop?
MSI970ag43 + gtx760 + gtx660 + Win10x64 = problems
No way to make both cards installed correctly/fully, no way to install eg different driver versions
for each of them, whats going on?!
Error 43 at best.