[Pc_Support] Future-proof PC motherboard?

[Bryan J. Smith]

On Fri, 2005-09-02 at 13:24 -0400, Damien McKenna wrote:
> http://www.anandtech.com/mb/showdoc.aspx?i=2521&p=3
> A motherboard from ECS that has a daughterboard for housing the CPU,
> with daughterboards available that support both current *either* AMD
> *or* Intel CPUs, with more in development including one for the
> forthcoming Athlon M2 series.

Yep.  HyperTransport makes it easy.  You can tunnel in whatever you
want.  That includes an additional HyperTransport tunnel with another 16
PCIe channels.

For Intel, the options are greatly reduced.  At most, they have a CPU
upgrade module.

Airma (IIRC) also has a HyperTransport upgrade module that lets you
switch between different CPUs sockets.

> For some perspective, there was a company several years back called PIOS
> (later renamed to Met at box) that had an engineer named Dave Haynie
> (ex-Commodore systems engineer) designing a motherboard + daughterboard
> system called the PIOS-One which would have allowed for something like
> that.  It is an extremely Commodore Amiga-like design to have the CPU on
> a daughterboard to allow easy upgrading later on (Motorola MC680x0
> series with some third-party PowerPC cards), and Haynie's board was
> initially aimed at the PowerPC "G3" and "G4" processor series.  During
> development Apple halted the clone market causing the non-Apple PowerPC
> system market to disappear almost overnight; when this happened Haynie
> went back to the drawing board to redesign his system to also support
> other CPUs (IIRC for the DEC Alpha), and it is IMHO/IIRC ultimately this
> redesign that caused the system's ultimate cancellation.
> So it is very cool to see "modern" motherboards starting to look at
> this.

The difference is that HyperTransport lends itself to such designs.
You can get extremely flexible with *0* redesign.  That includes
additional tunnels and other peripherals using HyperTransport.

Intel AGTL+ cannot.  At most for Intel, you have your PCIe channels out
off the daughtercard -- but that's it.  *0* flexibility in adding more
peripherals.

-- 
Bryan J. Smith     b.j.smith at ieee.org     http://thebs413.blogspot.com
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