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Table Of Contents  CertiGuide to A+ (Core Hardware)
 9  Chapter 0010:  CPUs
      9  IV  Older CPUs (80386 and 80486 Class)

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 80486-DX2
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80486

The 80486s were not groundbreaking in terms of a radically different design philosophy, like the 80386. It did have four new features that made the 80486 about twice as fast as the fastest 80386. The most talked about new features were a built-in cache, and a built-in math co processor. On average, the math co processor built into the 80486 yielded three times the greater performance than external 80387 Numeric Processing Unit (NPU).

Figure 32: 486 CPU socket. Notice the notched corner indicating Pin 1 placement. The pins are arranged to prevent incorrect placement, which would burn out the CPU.

 

The speed difference between the 80386 and the 80486 made the Graphical User Interface (GUI) practical for everyday use. Many consider this simple difference the primary reason why the 80386, once classified as too powerful to be exported (military considerations), is now worthless silicon.

[spacer]Inside the CPU

The actual CPU is hidden inside the packaging of what is commonly referred to as the CPU. This is to both protect the very small IC from handling as well as heat dissipation.


Using photomicrography and a little sharp shooting we bring you pictures of an 80486 CPU (Figure 33, Figure 34 and Figure 35.)


Figure 33: Close up of 80486 with cover removed.

 


Figure 34: Extreme close-up of the actual CPU displaying 1.2 million transistors. Notice the very thin wires connecting the actual CPU to the leads that continue to the pins..

 


Figure 35: Cross-section of the 80486 seen above. Notice how much ‘packaging’ is used for heat dissipation.

 

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