freebsd i386 on amd64 hardware?

Peter Wemm peter at
Tue Sep 28 16:57:16 PDT 2004

On Sunday 26 September 2004 07:05 pm, Joseph Fenton wrote:
> 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 socket.

My understanding was that the 939 socket had *all* of its pins 
reassigned to make it much easier to do a 4-layer board.  I really 
should go look at the pinout specs some day.  Not that it really 
matters though.. the pinout is different and that is what counts.

The folks who make motherboards by the million care about the cost 
difference between 6 and 4 layer boards.
Peter Wemm - peter at; peter at; peter at
"All of this is for nothing if we don't go to the stars" - JMS/B5

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