I would seriously consider a motherboard/bios, or memory incompatibility problem, rather than thinking you have found a problem in a processor. from six years ago.
Did you purchase the processor new, or used? Does it have ES on the processor lid?
just curious - how does one refurbish a processor, besides wiping the thermal paste off? To me, "refurbished" in this context is a [decieving] sales tactic. You may want to keep your receipt and prepare to send it back.