Fake Intel CPUs?

I recently purchased a processor off eBay that was labelled as an Intel Core i5-2520M. It came shipped in just a tray, not the original box, but the processor and all its markings look perfectly legitimate.

My system BIOS reports it as a Genuine Intel(R) CPU 0 @ 2.50GHz and shows the CPU-ID as 206A5, which, when I stick it into Google, turns up the Intel Core i7-2720qm instead.

The CPU seems to work fine for the most part and runs Windows 8 64-bit without issues, although it is giving me some trouble with AMT, but I'm not sure whether this is a CPU or a motherboard issue.

So, this leaves me with a couple of questions:

• Is it possible to update the microcode of a CPU to pass it off as a different one?
• Is it normal that a genuine CPU gets reported as "CPU 0" in the BIOS rather than its actual ID?
• Could this chip be an engineering sample?
• Is there a software tool that will check whether a processor is genuine?

I ran CPU-Z and it reports the following:

Name           Intel Core i5 2450M (hmmm...)
Code Name      Sandy Bridge
Max TDP        35 W
Package        Socket 988B rPGA
Technology     32 nm
Core Voltage   0.792 V
Specification  Genuine Intel(R) CPU 0 @ 2.5 GHz (ES)
Family         6
Ext. Family    6
Model          A
Ext. Model     2A
Stepping       5
Revision       D0
Instructions   MMX,SSE,SSE2,SSE3,SSSE3,SSE4.1,SSE4.2,EM64T,VT-x,AES,AVX

Should it look like this for a 2520M CPU?

It's an engineering sample (emphasis added):

Specification Genuine Intel(R) CPU 0 @ 2.5GHz (ES)

For more information, see this Intel page: Information about Intel Engineering/Qualification Sample Processors

Well, you got shipped a newer processor than what you ordered, with a marginally lower clockspeed and a few features disabled. Unless it was a hell of a deal, you might want to yell at the ebay vendor.

To sum up all the things in the comments and a few extra details - various levels of fake processors exist from repacked engineering sample chips, to the lovely, and utterly non functional core i7 920 newegg accidentally shipped a few years ago. You'd notice these are repacked chips, or complete bricks, rather than cunningly modified, or homebrewed processors.

In this case though, you got a newer core i5 2450 rather than an older, slightly faster 2520 which has a few additional features. While some intel processors can be softmodded to unlock additional cache and features, I couldn't find any reference to radical softmodding. While you didn't get what you paid for, the chip you have is probably as it was designed and manufactured by intel. I'd suggest taking a closer look at those chip markings - since they would confirm it. It would be possible, and a little crafty to swap those heatshields, but its unlikely since its too much work.

The product identification utility by intel might be of interest here as well