Gigabyte Z370 AORUS Gaming 5 Motherboard with i7-8700 Processor. In machine now Gigabyte Z97X (which has failed) and I7-4790K Processor, (4th Generation) OS Windows 7
OK, yes.
You need Win 10.
Even if it did theoretically support Win 7, you'd need to do a full reinstall anyway.
So you might as well go with Win 10.
Gigabyte Z370 AORUS Gaming 5 Motherboard with i7-8700 Processor. In machine now Gigabyte Z97X (which has failed) and I7-4790K Processor, (4th Generation) OS Windows 7
Gigabyte Z370 AORUS Gaming 5 Motherboard with i7-8700 Processor. In machine now Gigabyte Z97X (which has failed) and I7-4790K Processor, (4th Generation) OS Windows 7
OK, yes.
You need Win 10.
Even if it did theoretically support Win 7, you'd need to do a full reinstall anyway.
So you might as well go with Win 10.
+1^
It isn't the board that won't support W7, it is the Coffee Lake CPUs. In fact, some folks have gotten W7 to run fine with Coffee Lake CPUs. That board even has drivers for win7 in its support downloads. But yes, W10 is the safest bet.
Btw, this is why it is important to list your system specs when you post a question like that ;-)