Intel Pentium III Guia De Inicio Rapido página 2

Figure A
A
B
It is important that the Intel® Pentium® III processor fan heatsink aligns properly with
the 370-pin socket. Make sure to align the pin hole(A) with the PGA-370 mark(B) on the
socket. Proper alignment will ensure correct processor operation.
http://support.intel.com/support/processors
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