The CPU, a Small Journey

Written by: Gary Britton

We all know what the CPU is; some of us know how it works. To me it is a bit of a mystery how it does, all it does.

Here is an old AMD Athlon64 3500+, 2.2Ghz and it is about 1 9/16th” square. A pretty tiny device containing millions or billions of transistors, memory controller, instructions, and the heart of the computer, running a timer to schedule computer events – really small thing.

But what you were looking at is just a cover for the CPU itself, the die which contains all that wonderful and mysterious electronics and logic. Being a tinkerer I decided to pop the cap off this retired piece of electronics magic to see what was inside…..

And here it is the CPU die, the tiny square in the center of a green circuit board. This one has 14 smaller silicon blocks soldered around it with space for two more, possibly for making the same CPU perform differently. Note that it is it the exact center of the unit. People obsess over how/where/how much thermal paste to apply. This shows that the center of the cap is where one would need it to get it properly covered. The manufacturer uses a heavy-duty thermal to seat the cover to the CPU die.

The underside of the cover appears golden-colored in this photo, but looks like the outside of the cover to the naked eye, possibly some sort of shield? The cover isn’t attracted by a magnet, so it is stainless steel or some non-iron based alloy.

UPDATE: I have since found out the cover, aka IHS or Integrated Heat Sink is solid pure copper that has a nickel plating.

Here is a close up of the die and its board. The board material is opaque and must be multi-layered to connect the CPU and the 14 blocks to 939 pins (for this model) on the opposite side of it. These pins must fit perfectly into the socket on the motherboard, connecting everything to the many circuits on it.

The die is a small 5/16th” square and looks to be about 1/64th thick. The cover is solid and about 1/8″ thick. The CPU die must have hundreds of inter connected layers and sectors. These little guys do a helluva job for their small size.

This is a single core CPU and only 2,2Ghz. Changing out a motherboard once I bent the pins on my PhenomII X4, 3.4 Ghz, rendering it a paperweight. I decided to pop its top too to see the difference. To my surprise, the die in the 4 core CPU was the same size! I think that is amazing.

The 3500+ is 130nm (nanometer) technology, and the Phenom is 45nm. This is, as I understand, the diameter of the “wires” which are inside the CPU die connecting everything. The current Intel chips are 32nm. A nanometer is one Billionth of a meter.

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