AMD-64 large memory... -- 4-way v. 2-way dual-core ...

[Bryan J. Smith]

On Sat, 2005-03-05 at 22:17 -0600, dsavage at peaknet.net wrote:
> I'll be waiting a few more months until AMD releases dual-core Opterons
> before I try upgrading to a more affordable quad system with two sockets.

I don't think you'll be saving any money or price/performance.  Why?

1)  You'll only have (4) DDR channels in (2) Socket-940 versus (8) DDR
channels in (4) Socket-940

2)  The dual-core will be "EE" (55W low-power) logic (110W total) and
command a hefty premium, and aren't nearly the fastest.  E.g., the
current 240/840EE (1.4GHz) and 246/846EE (2.0GHz) versions are currently
70%+ extra, and still only the lower or mid-speed compared to the
availability of the 252/852 (2.6GHz) at about the same price.  It
wouldn't surprise me if (4) 8xx series CPUs of the same speed are the
same prices as (2) 2xx series CPUs with dual-core at the same speed --
including after the mainboard costs.  ;->

Then factor in the reality that most 4-way systems (like the AMD
reference design) have a 2nd AMD8131/8132 chip for I/O than the 2-way
systems and 4-way is typically better.  I could be wrong, especially if
the dual-cores sell so the "economies of scale" can take over.  But I
think that will _only_ happen for the Socket-939 versions, and not the
Socket-940 versions.  They will command a premium.

So you're losing DDR channels while paying a lot more for what you
actually get at 4-way.  At least for a server role when you need the I/O
-- especially for lots of threaded servers with lots of simultaneous
I/O.

Now if you just want CPU power, that's different.  Although if it's just
CPU power, then you're better off buying a 1 or 2 CPU system with an HTX
slot and setting up an Infiniband network for less cost.  ;->

Heck, I think the first mainboard manufacturer to introduce a Socket-939
mainboard with an HTX slot won't be able to meet orders -- especially
after the dual-core Socket-939s come out.


-- 
Bryan J. Smith                   mailto:b.j.smith at ieee.org
----------------------------------------------------------
Beware of those who define their preferences in terms of
hate of another option, than on the merits of their choice