Slot or ZIF?

Your choice of CPU will determine the type of motherboard you buy. Most current motherboards are either Slot-1 or Super Socket-7. Slot-1 motherboards support Intel's Pentium II and Celeron line of processors. There are also Slot-2 motherboards out there, but those are for the high end Intel Xeon processors. Intel has also released its next generation of Celeron processors with the new Socket-370 specification.

Intel's Slot-1 and Slot-2 standard has the CPU packaged with the L2 cache (BSRAM) in a cartridge, known as the SECC, Single Edge Contact Cartridge. The cartridge resembles an expansion card, and fits into a special CPU slot on the motherboard. Slot-1 has a 242-contact slot connector, while Slot-2 features a 330-contact slot connector. Basically, a Slot based CPU connects to a motherboard via a single edge connector instead of the multiple pins used in existing PGA (Pin Grid Array) or PPGA (Plastic Pin Grid Array) packages.

Intel's switch to Slot 1/2 was supposed to kill off the Socket-7, but AMD, Cyrix, and company have kept it alive and kicking. Socket-7 is the best known Zero Insertion Force (ZIF) socket. Zero Insertion Force sockets are those squarish CPU sockets that have a little lever on the side to hold the CPU in place. Inserting a CPU into the socket requires no force, greatly reducing the chance of damaging the processor pins during installation.

The Socket-7 and Super Socket-7, (Super7), motherboards support AMD's processors, Intel's Pentium processors, and offerings from Cyrix and Winchip. Normal Socket-7 boards only officially support the 66MHz bus speed, though many offer also 75MHz and 83MHz, respectively. Super Socket-7 motherboards take Socket-7 to the next level. Super7 motherboards have been quick to mirror Slot-1's move to AGP, the 100Mhz bus, and use of high-speed SDRAM. They are generally cheaper than their Slot-1 equivalents, and have the added benefit of being available in both AT and ATX form factors. AMD's current top of the line processors need the Super7's 100MHz bus speed.

In the mid 90's, Intel introduced Socket-8 for its Pentium Pro line of processors. Socket-8 weighs in with 387 pins compared with Socket-7's 321 pins. With the introduction of Slot-2 and the Xeon line of processors, Intel has abandoned Socket-8.

After losing control of the low-end market to AMD and Cyrix's recent surges, Intel has reentered the socketed CPU market with a new proprietary standard, the Socket-370. Featuring 370 pins and a nifty new PPGA (Plastic Pin Grid Array), Intel's newest Socket-370 Celeron processors are cheaper to manufacture than SEC cartridges and dissipate heat better than ceramic PGAs.