The Intel manufactured processors in the x86 line:
- i8088 - 16 bit processor. Started the line. Had an 8 bit external bus to reduce cost. Oddly enough, many were manufactured by future competitor AMD.
- i8086 - 16 bit processor. Started the line. Had a full 16 bit external bus. Not used much in PC's.
- i80286 - 16 bit processor. Introduced the 286 protected mode, which failed because it was rather clunky.
- i80386(DX) - Intel's first true 32 bit processor. Introduced 386 protected mode, which had all the proper memory management features any full fledged CPU should have. The "DX" nomenclature was tacked on when the 386SX (see below) was introduced.
- i80386SX - Identical to the 386 in function, but had a 16 bit external bus. This saved money on lower end systems.
- i80486(DX) - Basically, a 386 with a few extra instructions and an onboard cache. This cache improved performance vastly. It also integrated the x87 math coprocessor into the CPU for the first time. The "DX" nomenclature was tacked on when the 486SX (see below) was introduced.
- i80486SX - A 486 with a broken or disabled math coprocessor.
- Pentium Classic, or just plain "Pentium" - Intel's first x86 chip to use multiple instruction pipelines.
- Pentium Pro - A slightly improved Pentium which has a large in-package L2 cache. Cache and core ran at the same speed. Failed due to high production costs- if the cache chip OR the die were bad, the whole thing had to be junked.
- Pentium MMX - Added the MMX instruction set to the Pentium Classic processor. All Intel CPU's from this point on have MMX instructions available.
- Pentium II - The answer to the Pentium Pro cache problem: two separate packages on a PC board that plugs into a slot, known as Slot One.
- Pentium Xeon processors - Improved versions of the Pentium II, III, and 4, containing larger caches, and the ability to use more than two (or in the case of Pentium 4, one) processors in SMP mode. Intended to be used in servers.
- Celeron - A name for any number of stripped down Pentium II or III chips. Usually they lack cache, or run at a slower front side bus speed.
- Pentium III Katmai - Improved Pentium II. Has some extra instructions and runs at higher clock speeds.
- Pentium III Coppermine - An improved version of the Pentium III that has an on-die 256K cache and runs at higher clock speeds. Contrary to its name, it does not actually use copper interconnect technology.
- Pentium M - Mobile processor, based on the Pentium III with power saving tweaks. Actually does more work per clock-cycle than the Pentium 4, and requires less cooling, which has led to some people using it in fanless desktop systems.
- Pentium 4 - A partial redesign of the Pentium III, simplified in some aspects so that it can run at higher clock speeds. This is a marketing gimmick, of course; the CPU can run at around 3GHz but it doesn't do nearly as much per clock cycle as the older Pentium III.
The line starts to blur as you get into the Pentium II/III and Celeron series. There are many different versions of the Celeron, Pentium III, and so on. Please note that this list is in vague order of introduction; the "DX" versions of the 386 and 486 came before the "SX" versions. Also, /msg me if you find any errors.