freebsd i386 on amd64 hardware?

Joseph Fenton jlfenton at
Sun Sep 26 19:04:46 PDT 2004

Ketrien I. Saihr-Kesenchedra wrote:

> Bearing in mind that I don't work for AMD, my understanding is that 
> AMD has always planned on three sockets for the Athlon64 - 754 (single 
> channel), originally because it can be put on a 5-layer PCB. Socket 
> 940 for Opterons for dual channel, but requiring a 6-layer PCB. And 
> Socket 939 because that one less pin allows for 5-layer PCBs and dual 
> channel.

The 754 socket (one HT port and single-channel mem) was destined for
laptops. The 940 (three HT ports and dual-channel mem) needs the extra
layers for proper operation. The 939 keeps the dual-channel, but replaces
two of the HT ports with extra power and ground pins. All the extra power
and ground pins means less current surge and therefore needs fewer layers.
Making it one pin less keeps you from accidentally sticking it in the wrong

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