CertiGuide to A+ (Core Hardware)  9  Chapter 0010:  CPUs       9  V  Pentium Family CPUs

Pentium Pro 1 Xeon

As anyone who has used a Pentium Pro can tell you, this CPU had remarkable performance. The challenge Intel faced was the cost of production creating the Pro chip.

The built-in L2 cache had a high failure rate at Intel fabrication plants. How to get out of this pickle?

The answer lies in the Pentium II (P2). Intel began by separating the processor, and cache of the Pentium Pro, mounting them together on the circuit board with a big heat sink.

Then by dropping the whole assembly onto the system board, using a Single Edge Contact (SEC) with 242 pins in the slot, and adding the 57 MMX micro-code instructions, then Intel had the Pentium II.

This way, defective cache modules don't force throwing out of a perfectly good CPU, because of a bad cache. And to further improve cache yields, the Pentium II ran cache at half the speed of the CPU.

Due to reasons beyond the scope of this work, the PII was limited to 512 MB of system RAM. That was repaired with the release of the PII 333Mhz.

Pentium Pro 1 Xeon