configurable HT speeds.

[Stefan Reinauer]

Hi,

as far as I see CPU-CPU HT links are configured with 800MHz at max.
C0 and newer K8 CPUs should be able to do 1000. Is there any reason not
to enable this in such case?

Also, if there happened to be 8131 which do 800MHz on the link,
can we make this configurable via cmos or is Config.lb the way to go
that early?

Stefan

Stefan Reinauer  writes:
> Hi,
>
> as far as I see CPU-CPU HT links are configured with 800MHz at max.
> C0 and newer K8 CPUs should be able to do 1000. Is there any reason not
> to enable this in such case?

This one is subtle.  AMD does not really talk about cpu to cpu
link speed.  But there is no support of 1000Mhz being supported
until we get to the newest generation of chips coming out.

In addition I measured it on a dual cpu system and I could not
detect a performance difference based on the link speed so I decided
to play that one safe.
> Also, if there happened to be 8131 which do 800MHz on the link,
> can we make this configurable via cmos or is Config.lb the way to go
> that early?

The 8131 very clearly has an errata that as I recall was labeled
wont fix that limits the link speed to 600Mhz.

Eric