The size and spacing of the processor's transistors (silicon etchings), which partially determine the switching speed. The diameter of transistors is measured in microns. One micron is one-millionth of a meter. The 90 nm (a nanometer is one-billionth of a meter) process combines higher-performance, lower-power transistors, strained silicon, high-speed copper interconnects and a new low-k dielectric material. For more information see: http://www.intel.com/technology/silicon/nanotechnology.htm
Chipset
The motherboard chipset consists of a north bridge, or Memory Controller Hub (MCH), which is responsible for controlling communication between system memory, the processor, AGP, and the south bridge, or I/O Controller Hub (ICH). The ICH controls communication between PCI devices, system management bus, ATA devices, AC'97, USB, IEEE1397 (firewire), and LPC controller. [These controllers are soldered onto the motherboard and cannot be changed or upgraded.]
Clock Speed
The speed at which the processor executes instructions. Every processor contains an internal clock that regulates the rate at which instructions are executed. It is expressed in Megahertz (MHz), which is 1 million cycles per second or Gigahertz (GHz), which is 1 billion cycles per second.
Front Side Bus Speed
The speed of the bus that connects the processor to main memory (RAM). As processors have become faster and faster, the system bus has become one of the chief bottlenecks in modern PCs. Typical bus speeds are 400 MHz, 533 MHz, 667 MHz, and 800 MHz.
L2 Cache
The size of 2nd level cache. L2 Cache is ultra-fast memory that buffers information being transferred between the processor and the slower RAM in an attempt to speed these types of transfers.
L3 Cache
The size of 3rd level cache, typically larger then L2. L3 Cache is ultra-fast memory that buffers information being transferred between the processor and the slower RAM in an attempt to speed these types of transfers. Integrated Level 3 cache provides a faster path to large data sets stored in cache on the processor. This results in reduced average memory latency and increased throughput for larger High-end Desktop workloads.
Memory Type
Random Access Memory (RAM) is fast but temporary data storage space. Each chipset supports one type of memory: SDR SDRAM, DDR SDRAM, or RDRAM. SDR (Single Data Rate) SDRAM and RDRAM (Rambus) are older memory technologies that are no longer supported by current Intel chipsets. DDR (Double Data Rate) SDRAM has two transfers for every one transfer with SDR SDRAM. Dual Channel DDR SDRAM transfers data four times for every one transfer with SDR SDRAM. For more information click here.
Other Intel Technologies
HT Technology: The abbreviation 'HT' stands for HyperThreading, a technology available in some Intel® Processors. If an application or motherboard is 'HT Enabled', it will support HyperThreading technology. See: http://developer.intel.com/technology/hyperthread/
Package
The physical packaging or form factor (size, shape, number and layout of the pins or contacts) in which the processor is manufactured. There are many different package types for Intel® processors. See the Processor Package Type Guide for photos and details.
Pin Count
When processors are manufactured using pin grid array (PGA) packaging, the back-side of the processor has protruding pins. The amount of pins on the processor, along with the layout of the pins, is a gating factor for which processors a particular motherboard can support. The socket that is soldered onto a motherboard cannot be changed, so only pin-compatible processors will be supported.
Slot/Socket Type
A motherboard is designed for a certain range of processors. One of the determining factors of processor compatibility is the slot or socket connector soldered onto the board. 242-contact and 330-contact slot connectors were used for a short time to allow for L2 cache to be packaged close to the processor die. Processor manufacturing advancements now allow L2 cache to be manufactured on the same die as the processor, requiring a smaller form-factor processor packaging. PGA (pin grid array) sockets are more common, flexible, and compact, but have many variations in the amount of pin connects and pin layouts.
sSpec Number
Also known as specification number. A five character string (SL36W, XL2XL, etc.) that is printed on the processor, and used to identify the processor. By knowing the processor's sSpec Number, you can find out the processor's core speed, cache size and speed, core voltage, maximum operating temperature and so on.