After the BIOS update the Haswell i3-4150 is now working :D It gave me a brief scare after swapping CPUs in that it failed to power on at all. But removing the CMOS battery seemed to clear that up. And I was able to use IPMI to access the BIOS settings. I think the thing I was forgetting was to "push del repeatedly" – I had been holding del down which doesn't work. So now I just need to install the MOBO and drives into the case and I should be good!!