When buying CPU's off ebay, how do you 100% guaruntee its geniune?

[Jack the Stripper]

Are there tests you can do?

Or is it simply installing the CPU and running CPUZ or letting Windows recognize it.

I am thinking about ordering a CPU from China but I am very worried about not getting the genuine article. See they can counterfeit so many things over there. I know its probably irrational to think that a North American would never do it.

[Energycore]

You can't guarantee before receiving it, but if it's not what you ordered (provide proof like a photo of the Windows thingy), ebay will most probably give you back your money

[Chewique]

Maybe you could get them to send you proof? Like a video of them putting the CPU in then showing you the CPUz or something? 
To be fair, i dont think there is much you can do apart from that.

[Droidbot]

Installing the CPU and running CPUZ is your best bet. What CPU, and could you give us a link?

 

I've seen counterfeit CPU packaging before for a 4770k with a LGA775 Pent4 inside, but not proper counterfeit CPUs. 

I guess get it, and if it's fake then just chargeback on PayPal?

 

[Jack the Stripper]

That is what I am thinking, I dont think anyone can spoof the CPU id system. Its easy enough for them to print something on the cpu case though so thats why I ask. Yeah the packaging can totally be easily counterfeited.

 

Just eye balling some Xeons, sometimes there is a big jump from the handful of cheapest ones to more expensive units. But all in all they are all very reasonably prices, X56yy Xeon's. Its just that the CPUbenchmarks go from X5650 and X5690 and no inbetween. But I am guessing I can correlate a linear pattern from the 2, am I right? What do I mean by that? Well lets say on a graph, you mark the lowest X5650 and the highest X5690 and you connect the dots, so a X5650 is close to a X5660 (both are 6 cores)