Sockets and Slots
- the CPU holders -
*** for details, see the Intel Packaging Databook
Nothing causes more confusion than the combinations of sockets, slots, motherboards, and memory. No one will ever understand it all, so you are not alone. Here we will take a stab at it, and leave out the oddball designs. We will concentrate on the more popular Intel designs, and leave out AMD (Slot A).
Slots were never fast enough, because the CPU rose above the motherboard, which forced the circuitry to have longer leads. The sockets mount directly to the motherboard and therefore allow top speeds with their very short leads.
Slot 1 (SC242) - 242-pin connector for Pentium II (and the early PIIIs) as well as old Celeron processors. Slot 1 is a long slot, that looks like a RAM slot, except it has black plastic guides on either end. Slot 1 only allows the L2 cache to operate at 1/2 the CPU speed !!
Slot 1 CPU - the CPU uses an SEC (Single Edge Contact), which is a small board with edge connectors that mounts vertically in the slot. Most SEC's come as enclosed cartridges - a black plastic housing as shown below :
Slot 2 - 330-pin connector for Pentium II Xeon and Pentium III Xeon - very pricey motherboards !! Slot 2 is physically similar to Slot 1, however, the CPU is much taller !! Slot 2 allows the L2 cache to operate at full CPU speed !!
Older Sockets - the 486 uses a 169-pin socket. The Pentium (PI) uses a 273 or 296 pin socket. Pentium Pro uses a 387-pin socket.
Socket 7 - 321-pin white plastic square mounted flat on the motherboard with a metal swivel arm that locks the CPU pins into place. The dimensions of Socket 7 and 370 are the same.
Socket 370 - 370-pin white plastic square mounted flat on the motherboard with a metal swivel arm that locks the CPU pins into place. Used with the PIII and AMD K6. The dimensions of Socket 7 and 370 are the same.
Socket 478 - used for the P4 - 478-pin, smaller size than Socket 7/370 which allows faster speeds (the more compact, the smaller the transistors, the faster the speed):
