what ram are you using? try using just one stick at first if you're really stuck.

try loose subtimings to rule them out as well. 5-5-5-15-6-42-4-11-7-13. ram 1:1, not 4:5. static read off. try 105 pcie.

You shouldn't need more than 1.4vnb, but try as high as 1.55v for the time being (do note until you verify vnb with dmm, you can't trust what you set)

vfsb should be fine at stock, but bump it one if you must.

how hot is the nb getting?