Starting off, there are two major players in the CPU industry, Intel and their rival AMD.
Something you should know about a CPU is that it has a system bus which carries info into, and out of the CPU. When the system bus enters the CPU it is usually referred to as the Frontside bus, the frontside bus is normally equipped with a 64bit wide data path. In the CPU you have a controller including one or more ALU’s and the internal cache. * ALU – Arithmetic Logic Unit *responsible for performing complex calculations*
Having multiple ALUs in a single processor is what gave the earlier Pentiums their processing capabilities. Communication between the ALU and the controller uses a 32bit wide data bus. The Bus connecting the CPUs cache to the ALU & the controller is referred to as the Backside bus.
CPU Speed * Processor – Usually measured in GHz. * System Bus – Usually measured in MHz *limiting factor of 800MHz* * Multiplier – Ratio between processor and system bus. *system bus speed x multiplier = processor speed.
Multiprocessing – The ability to perform multiple functions simultaneously. *True multiprocessing requires multiple processors.* * SRAM – Static RAM *faster but more expensive, holds memory w/o being “refreshed”.* * DRAM – Dynamic RAM *memory must be “refreshed”
Cache
* L1 Cache – Located on the CPU chip * L2 Cache – Located inside the processor housing, but not on the chip * L3 Cache – Located inside the processor housing also, but further away from the Processor chip.

Sockets * LGA 775 – (Intel) Pentium 4 & Celeron * Socket 754 (AMD) Athlon, Sempron, Opteron
Zero Insertion Force
ZIF – Term for the placement of the CPU in which the lever seen on a motherboard is used to lock the CPU in place without damaging it, or the pins it connects to.
Heat
Optimal temperature is between 90 and 110 degrees Fahrenheit (32-43 degrees centigrade) you can check the system temperature in CMOS. A thermal compound is used to form a seal on top of the CPU and then a heat sink is attached on top, usually with a fan on top of that. A heat sink looks like a flat piece with fins protruding out of it.