Okay, I've solved the voltage thing.
Different programs show different things. AIDA64 says I'm at 1.3V, a reinstalled CPU-Z is insistant it's 1.43V, Sandra is saying 1.3V.
The bios shows CoreVID as 1.300V, but it shows CPUCoreVID as 1.432V. Still not sure why it's 1.432 when it's set to 1.37, but I want it at 1.43, so its all good I think.