What are these Clusters of Tiny Components on the Underside of my MotherBoard in my PC?!?

Question

I just took the Panels off of my PC I built last January. I figured I should check for Dust, and clean it out. I noticed that on the Back (Underside) of my MotherBoard, there are 3 Clusters of Tiny Components.

I remember seeing them before, I just never realy thought that much of them. But what made me so Curious, is that I finally noticed that 2 of these Clusters are underneath the North & South Bridges.

Their is a Small Cluster right underneath of the CPU (K8).
I knew this before.
Their is a Larger Cluster right underneath of the North Bridge.
Their is also a similar sized Cluster underneath the South Bridge.

Now, this got me Thinking!! Why are they underneath these Key Locations? And what are they for?!? What do they Do?!?

Could these Clusters of Components be Sensors to Detect the Temperature of the North & South Bridges?!? As well as the CPU?!?

I have a Program called SpeedFan, which show I have 5 Sensors, 3 of which are controlled using my IT8705F I/O Chipset. I can't seem to Identify these 3 Sensors. Could these Clusters be them?!?

Yes, these Components are Really Tiny!!!!

Here is a Website I found with the Picture of the Underside of My MotherBoard. Here, you will see the 2 Large Clusters, and a Small Cluster under the CPU:

www.overclockersclub.com/imageview/?/images/foxconn/image-27.jpg

www.overclockersclub.com/imageview/?/images/foxconn/image-27.jpg

www.overclockersclub.com/
imageview/?/images/foxconn/image-27.jpg

Answer 1

Are these really tiny? They are probably surface mount capacitors and possibly also surface mount resistors. The capacitors are probably being used to filter noise and EMI from the DC supply tracks for the chips. Also some devices use external capacitors to generate timing signals.

Answer 2

The MoBo manufacturer had to modify the main board after manufacture to make it work properly.