Subject: Re: CCL:Summary Opteron vs Nocona

From: Mark Hahn <hahn^at^physics.mcmaster.ca>
Date: Tue, 17 May 2005 13:11:40 -0400 (EDT)

> > However, there's one point about opterons. AMD just announced dual-core cpus,
> > which should perform far better than the single-core shipped now.

for cache-friendly applications that don't mind somewhat lower clocks.

> whatever time period of choice :-) I don't think it in general is worth 
> waiting for the next family of CPU's. Instead, get what is available when 

it depends on how advantageous the change is.  for instance, if you are 
heat or footprint-constrained in your machineroom, AMD's dual-core might 
well be worth waiting for, since they are compact and noticably cooler 
than two single-core chips.

> price/performance ratio of dual cores would be, at least in the beginning, 
> when counting in all the costs of motherboards etc.

if you have cache-friendly code, dual-core is very effective.
other components are basically the same, therefore no price premium.

AFAIKT, AMD hasn't announced DC pricing yet:
http://www.amd.com/us-en/Weblets/0,,7832_8366_609,00.html
the premium for 8xx chips is noticably higher than twice the 
price of the same-clock single-core.  but of course you save 
with fewer motherboards, chassis, etc.

> Also, after the dual core chips ship, there will be a lag before proper 
> drivers/kernel patches for Linux appear. It took a year after release 

no, DC is such a minor architectural change that it's already supported.

regards, mark hahn.
sharcnet/mcmaster