Pentium PRO

Posted by Harisinh | Posted in | Posted on 4:32 AM

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Towards the end of 1995 the Pentium Pro was announced. This Pentium introduced a new socket (Socket 8), utilizing 387 pins. The Pro series included ability to run multiple instructions in one cycle, could execute instructions out of order, and had dynamic branch prediction, as well as speculative execution. Also included was an
impressive cache arrangement. For programmers, the Pro looks like a classic CISC CPU, while internally the CPU is very RISC oriented in design.

This 3.3 Volt CPU (3.1V at 150 MHz) was designed with a 32-bit operating system (OS) such as Windows NT in mind. While the Pro had Level 1 cache in the CPU, its real forte was the integrated Level 2 cache which allowed upwards of 1MB of cache to reside inside the CPU packaging to run at processor speed. This really improved performance in SMP based system boards. The Pro chip was the first chip to be offered in the AT or the ATX format.

The ATX format was preferred, as the Pro consumed more than 25 W of power, which generated a fair amount of heat. There were several major improvements of Pentium pro over Pentium, for example it had a superscalar architecture (microprocessor architecture containing more than one execution unit), 12-stage super pipeline, internal micro-ops similar to RISC like instructions and internal thermal protection. This microprocessor could be clocked to 200.00 MHz and consisted of 5.5 million transistors.


Pentium PRO Microprocessor

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