Not only must it fit and you have slots with enough PCIe channels but there's power requirements (think Amperes not Watts!)
After all that you have driver hell to work through. I usually do the BIOS, motherboard then GPU drivers but some insist on try Microsoft's Update Driver Button which is a ticket for fun swamp rides.
Hi im Glenn i got this bulid I7 6700k asus 170 progaming 32gb ddr4 ram msi 1070x 8Gb i want to opgrade my gpu with this 2 x msi 1080ti 11gb is it possibble? wil i works ?