How Pentium Upended an Industry
Few CPUs had quite the impact on the processor market as the original Pentium. The first x86 processor to get a name, it marked a quantum leap for personal computers.
What Made the Pentium Special?
The Pentium introduced at a time when Intel was feeling the heat from various competitors who were also manufacturing 486 processors that could market as essentially the same product as its CPUs. In order to stop that from going any further, the company coined the Pentium name and introduced a wholly new design to go with it. Among other things, it brought the following features to the table:
- Superscalar Processing: The Pentium was the first x86 design to introduce parallel processing with a second execution unit that let the CPU process two instructions simultaneously.
- 64-Bit Data Bus: Where the 486 series relied on a 32-bit memory access architecture, Pentium doubled that to 64-bits, which gave the processor much more bandwidth regardless of the speeds involved. The fact that the memory went from a maximum of 33 MHz to a minimum of 60 MHz didn't hurt performance either.
- Branch Prediction: In order to avoid pipeline stalls, the processor tried to predict which branch of an instruction would be followed so that it could keep working rather than waiting for results. When it guessed right, it led to a significant increase in speeds.
What About Socket 5?
The Pentium used three different socket architectures during its lifetime: socket 4, socket 5, and socket 7. Each supported different generations of Intel Pentium processors, although socket 5 CPUs are also compatible with socket 7. It's always a good idea to check the compatibility of a CPU before looking for a motherboard:
- Socket 4: The 273-pin socket 4 supports only the original 5-Volt Pentium 60 and 66 MHz.
- Socket 5: The 320-pin socket 5 supports the 3.3-Volt Pentium 75 through 133 MHz models.
- Socket 7: The 321-pin socket 7 supports all 3.3-Volt Pentium and Pentium MMX CPUs from 75 to 233 MHz.
Using the Pentium
The Pentium did more than just give people a target for CPU upgrades. With the socket 5 system and its successors, it provided a great leap forward for home computers that made hardware exciting again. When working with compiled code it was much faster than any of its predecessors, and the overdrive system made it possible to put a new CPU in an older motherboard for a significant increase in performance. As always, it did take a while for software to catch up with the hardware but once it did the industry never looked back and the superscalar approach became the new standard.