Subject: Re: CIA bridges never use BWX capability
To: None <>
From: Jochen Kunz <>
List: port-alpha
Date: 04/10/2004 10:52:27
On Sat, 10 Apr 2004 02:37:19 -0400
Sean Davis <> wrote:

> Do all 21164s do BWX? I was, according to something I read long ago,
> under the impression that only the 21164A had this capability.
AFAIK only EV56, but not EV5 has BWX. (Boot your AS 600 5/266 and you
will see.)

> I own an
> AlphaStation 600 5/266, with a 266mhz 21164, and I'm wondering if
> fixing the BWX-enabling stuff would help its performance any. Compared
> to my Ultra 5, at 270mhz, with the same amount of ram and twice as
> much L2 cache (but no L3, the Alpha has 2MB of L3), it runs pretty
> slowly.
Well. Alphas need a lot of MHz to get the same performance then other
CPUs due to the pipeline lenght. E.g. a 500 MHz EV56 has about the same
SPECint95 rating as a 360 MHz Sun US II, or a 300 MHz MIPS R12k or a 240
MHz PA-RISC 8200.