FS Cooling Guide: CPU Cooling
The P3 TF by Tennmax
Pentium IIs ushered in a new era of aftermarket cooling. They had millions of transistors on them, causing the first-generation Klamath core PII's running on a 2.8V core voltage to run very hot. The anemic coolers that Intel provided with their retail boxes steered many do-it-yourselfers towards the OEM versions of PII's, which came free of fan and heatsink. Then, the aftermarket selection was and still is quite varied for the various models of PII's.
If you have a PII and intend on buying an aftermarket fan, make sure you get one for the PII. While this is perfectly ridiculous logic, there are a lot of Slot-1 fans out there. Don't forget, Slot-1 encompasses Celerons, PII's, and PIII's. While the CPU interface is similar, the CPU's housing are different so you need to get the right fan that will fit well and provide good contact with the CPU. PII's can be in one of two interfaces: SECC-1 or SECC-2. SECC stands for Single Edge Contact Cartridge, and defines the PII and PIII's "housing". SECC-1 is the first generation of PII's which had the black cartridge covering both sides of the CPU, so the whole thing looked like a black rectangle. This was not as effective for cooling purposes, because it added an additional layer of metal between the heatsink and the CPU and cache chips. Later, Intel released the SECC-2 cartridge for PII's, which is also the housing for PIII's. The SECC-2 cartridge is kind of a hybrid between the fully clothed SECC-1 and the naked Celeron. The SECC-2 is covered on one side, and uncovered on the other. The reason for this was to allow cooling directly to the CPU, rather than having to deal with the metal plate that was on the SECC-1 cartridge. This is an SECC-1 PII: