I was planning on using the CPU to flash my BIOS so I can use a V4 xeon, then return it for a refund. Technically, this is entirely within your rights with the Distance selling regs, you have 14 days after taking delivery to open it, try it out, and return it so long as the packaging is in a resellable condition - breaking seals is fine, but tearing the whole box across the front isn't.
I did the same thing when I bought a new keyboard. Since they're a subjective thing, I couldn't decide between a Razer blackwidow chroma, or the Corsair K95 something or other. So I bought both, tried them both out for a couple of days, then returned the Corsair, after giving it a nice thorough dust and putting everything back into the box the way I found it, plastic bags and all. Someone else buying it wouldn't know it was a return. I would have no problem buying a return in this manner.