What is the purpose of the Circuitry beneath a CPU

[necrontyr]

Hey guys, this is prolly a very rudimentary question, i did a few searches online and came up with nothing. I have a massive head cold too so i prolly missed the most obvious articles...

But here it goes, on page 1 of this article http://www.anandtech.com/show/4083/...el-core-i7-2600k-i5-2500k-core-i3-2100-tested at the very bottom is an illustration of the 1156 cpu versus the 1155 sandybridge chips, in that illustration it shows the circuitry anyone who has reseated a cpu has seen before....

And i would just like to know does anyone know what that block of circuitry in the centre of the cpu does, why its on chip, and how it works ?

Any articles about cpus that mention it would be appreciated too.

Thanks

 

[Tealc]

Looks like a bunch of SMD capacitors, although not sure what the blue ones are for. Capacitors are normally used to smooth power so maybe it's something to do with that.