If you have a particular board in mind, say an asus - I'd give them a call and ask to be sure. Some have a way to flash the bios via usb, others require you have an older support cpu installed to be able to update the bios to accept the new cpu. It's one thing if you've got a b85 mobo and cpu already and just looking to upgrade the cpu, you'd at least have the means to update it if the cpu is needed (non usb bios flash). It can cause problems if it's a new purchase if someone gets a new cpu and an older motherboard that aren't natively compatible with one another unless they have a friend with a spare compatible cpu to temporarily install.