What are the little things on the underside of a CPU?

[Dangerous_Dave]

1) As per title - wondering what those small components on the underside of a CPU are and:

2) How important are they for functioning? Would you expect no functioning if some missing, or partial?

 

[Dangerous_Dave]

Naw somebody sent me one sans stuff on the bottom. Without noticing the missing bits on the bottom, I tested it and it seemed to be working, and ultimately I resold it. Buyer complained that it had bits missing off the bottom - chip comes back and lo and behold it does! BUT it's STILL working!? So now i'm wondering what that stuff actually does.

 

[Dangerous_Dave]

This is original :

This is mine:

 

[Dangerous_Dave]

Not just one or two - more like about 9!

 

[Dangerous_Dave]

It does work - at least appears to. Boots windows no problem.