Yeah def hynix, says hynix in UEFI and in CPUz memory tab.
When it wouldn't start 6200Mhz I had already set bclk set to 100 so I knew they where 6200 and not way over that clock, which is the XMP frequency for the kit, XMP on this kit is 6200 36-39-39
I've tried G7400 and 12100F now, so I think I'm safe in assuming its not the CPUs since they both seem to exhibit the same behaviour, which leaves three possible options, the memory kit, the board or I'm useless haha
I'd like to try G.Skill 6400Mhz C32 kit but spending £400 on another memory kit just to possibly find its not that is unpalatable lol
Best I've gotten in GB3 Multi on the 12100F, having issues getting into windows now. Login screen is being weird.
EDIT 2
Memory set at 4800Mhz and best I can do is 118Mhz BCLK, the above screenshot was at 3600Mhz set and could manage 122Mhz BCLK