Strix B450-F. With the 3600 it all powers up but no display and an orange light on the motherboard. I've read online that the likelyhood is that it needs a BIOS update.
So I ordered a AMD Athlon X4 950 Processor from elsewhere with the intention to flash the board and then return it. With that CPU in, it doesn't even power up. Perhaps DOA but I'm skeptical. I've arranged a return and I've now ordered a AMD Athlon 200GE but I'm not convinced it'll work, sadly it doesn't turn up until later in the week.
The build is for my mrs work mate, he's only a young lad (18 I think) so I'm keen to get it all working for him. His current rig is very old and keeps crashing/not running games and I'd agreed to build it all for him if he bought all the parts. I made the mistake with the board recomendation needing an update so I've used my own money for the 'flashing' CPUs.
I'm not sure if it makes any difference at all but the GPU is a 1080 Ti.