Introduction and History Lesson
The Intel Corporation has been making processors and peripherals for computers for the better part of 10 years, and for 8 out of the 10 years Intel has led the industry with the fastest processors for desktops, servers and workstations.
Intel's first 32bit CPU was the Intel i386DX processor line. Codenamed "P9", it supported frequencies of 16Mhz up to 33Mhz (using 16-33MHz FSB).
Intel in June 1988 released its Cut-down version of the i386DX, named the i386SX. The primary difference between the DX and SX was cache. While the DX line supported no L1 cache and up to 128KB of L2 cache on the motherboard, the SX supported NO L1 or L2 cache at all, making it somewhat slower than its DX counterpart.
In response to the AMD 386 and IBM 386 line of CPU, Intel decided that increasing the speeds of its 386 line wasn't enough to keep Intel on top. In April or 1989, Intel released to the public the first CPU with a Math Co-Processor or better known as an FPU. This alone gave Intel the crown for fastest CPU, but Intel didn't stop there. Keeping with Intel's style for new innovative designs, the CPU was given a L1 cache size of 8Kb and a L2 cache access size of up to 512Kb or cache on the supported motherboard, this new creation was dubbed the i486DX.
AMD responded to this by releasing their 486 line of CPU, and this proved to be a hit in the low cost market. Intel, not happy losing out to AMD in sales took the i486DX, removed the FPU and sold the chip as the i486SX CPU, taking back what Intel had earned.
With bus speeds approaching their limit, Intel, AMD and Cyrix tried to get their CPU's to run faster, but expansion devices like hard disks and video cards became unstable as the faster CPU's pushed the limit of the bus speeds. Intel answered this challenge by introducing what we now know as the clock multiplier into the CPU. This clock multiplier was set to 2x, and Intel named this CPU the i486DX2 processor. The i486DX2 used the bus speed x2 to increase the CPU speed. This step is still implemented today in our latest processors.
Continuing with the trend, Intel incorporated a 4x multiplier into its next line of 486 class of CPU. This CPU was named the i486DX4, ranging in speeds from 75MHz to 100MHz this was the last 486 CPU to be made by Intel.
In 1993, Intel released a new bus standard. Known to the world as the P5 bus, this new architecture lead to a lot of new processors from Intel and its competitors as we will soon see.
The first of Intel's P5 CPU's was the Intel Pentium. The Intel Pentium came in speeds of 60MHz up to 200MHz using 50MHz to 66MHz bus speeds. This new CPU introduced another of the new CPU standards which are still used to this day; divided cache. Divided cache technology incorporated two separate cache chips on the L1 platform, 1 set for data, 1 set for instruction. This helped boost the power of the FPU system.
With the computer market swinging to the home user rather than just the business user, Intel needed to boost it P5 CPU line to support better gaming. Intel took the existing Pentium CPU and added a new Multimedia Xceleration (MMX) technology. The MMX system was a new set of 50 instructions added to the CPU for handling number crunching. This new CPU was available in speeds of 166Mhz up to 233Mhz, the MMX Pentium was the last P5 CPU made by Intel.
Intel's most recent line of CPU's was based on the P6 bus introduced by Intel back in 1995 with the Intel Pentium Pro CPU. The Intel Pentium Pro CPU was released in November 1995. This CPU was the first of Intel's line of CPU's to introduce on-die L2 cache. This new cache technology allowed for faster L2 cache access speeds since the L2 cache of the Pentium Pro ran as same speed as the CPU's core. The Pentium Pro was built mostly for servers and workstations but around the time that the Intel Pentium MMX arrived, the Pentium Pro found its way into a few of the home users systems. While this CPU was a good performer with the L2 cache on the CPU, it still lacked the support for MMX applications.
With the need for the Pentium Pro to support MMX instructions, Intel took the Pentium Pro CPU, moved the L2 cache off the die and added the MMX instruction set, and in May 1997 Intel gave birth to one of the best CPU's Intel had ever created, the Intel Pentium II. The Pentium II was a Slot 1 based CPU since the cache had to be moved off the die to save on costs. But to increase the speed of the cache by having direct access to the CPU, Intel created a slot connector for the Pentium II.
With AMD and its K6-2 and K6-3 taking the value market away, Intel needed a new value market CPU. Intel took the existing Pentium II core and totally removed the L2 cache, naming this new CPU the Intel Celeron. The first wave of Celeron CPU's were a disaster. With no L2 cache the CPU ran slower than the AMD K6-2 and cost more than a K6-3. This didn't go down well so Intel decided to take the Celeron core and add 128KB of on-die L2 cache running at the core clock of the CPU and named it the Celeron A series. The Celeron A series started out in Slot 1 format, however, with the L2 cache integrated into the CPU there was no need for the expensive slot configuration so the Intel Celeron A moved over to the Socket 370 PPGA connector and has remained there. Intel's newest Celeron CPU, known to us as the Celeron II, is based on the Intel Pentium III FC-PGA package. This new CPU is the same old Celeron core and the same amount of memory. The only difference is the reduction in size of the DIE and the transfer from 64bit cache to 256bit ATC.
Intel's fastest and mainstream P6 CPU is and was the Intel Pentium III CPU. The Pentium III started out as a Slot 1 CPU but later moved to the Socket 370 FC-PGA packaging when the cache was moved from the Slot to the die of the CPU. The Pentium III's main feature over the Intel Pentium II was new multimedia instructions called SSE. These new instructions gave the Pentium III a slight boost in the benchmark department.
With the AMD K7 line of processors taking the fame away from Intel during the i820/RDRAM/SDRAM disaster, Intel had to come up with a new CPU in order to take back the crown from AMD. Enter the Intel Pentium 4.