Yes, a Windows 8 ISO from Microsoft can run with a valid key on UEFI.
Yes, a Windows 8 ISO from Microsoft can run with a valid key on UEFI.
You're looking to set up Windows 8 on your Maximus VII board with a Samsung 840 EVO SSD as the primary boot drive. You're considering purchasing a Windows 8 installation media that will likely include a disc and CD key, but you're planning to use a USB drive for booting. Since you don't need a physical CD for day-to-day use anymore, you want to ensure compatibility with UEFI systems. It's important to note that installing Windows 8 directly from a USB without the official media might cause issues, especially if your system is UEFI-based. You should verify the latest requirements and consider using a bootable USB with the correct ISO image for Windows 8.
I believe Microsoft still permits downloading the ISO file. You might have found it using 7, but I think it's become more difficult to locate. If you can't find it, you could obtain an ISO from a torrent. Avoid entering the CD key during installation and consider getting one from Microsoft or another source. The key should function properly as long as it matches the edition you originally downloaded (home, pro, or enterprise).