[NTLUG:Discuss] Re: OT: New Hardware Question

[Bryan J. Smith]

On Wed, 22 Dec 2004 06:55:33 -0600, Dennis Myhand wrote:
> Well, sometime today I will have all the parts gathered for my new
> system.  I will be building an AMD 64 3000+ system

Socket-754 or Socket-939?

If Socket-939, might as well go nForce4 now that it's out with
PCI-Express.  Not so much for video, but for other I/O -- like keeping
your ATA and NICs _off_ of the same PCI bus as audio and other I/O that
cause latency otherwise (e.g., "choppy audio").

The two nForce4 mainboards I've seen shipping are:  
  ~$120   nForce4       Gigabyte GA-K8NF-9
  ~$300   nForce4 SLI   Asus A8N-SLI

For the most part, unless you are going to use a PCIe x4 or x8 storage
controller and a PCIe x16 video card, or two PCIe x16 video cards, the
SLI is not much of use.  I haven't verified that SLI even works in the
Linux nVidia drivers yet and under Windows, it only helps applications
written with _specific_ approaches that the drivers can handle.

At ~$120, the Gigabyte GA-K8NF-9 becomes a no-brainer.  With ATA and NIC
on their own PCIe x1 channels, it's the commodity segmented I/O that
desktops have been longing for awhile now.  In addition to the PCIe x16
for video and (2) PCIe x1 slots, you still have (3) legacy PCI slots for
other peripherals (and some of the other, lower DTR, on-mainboard
components use them as well).

> and I have been having a little trouble gathering some information about
> temperatures.  Does anyone know where I can find what would be the
> upper limit for processor temps?  I have looked at AMD's site and
> the only thing I could find was Max Case Temp.  I wwould like to know
> just when I ought to start worrying, if possible.  Thanks, Dennis

Because most people believe the mainboard thermaresistor below the CPU
is the "CPU temperature," si AMD has accommodated its specifications as
such.  AMD, like Intel processors, are typically rated for 80-100
degrees Celsius _internal_.  This comes out to about 50-70 degrees
Celsius at the thermaresistor _below_ the CPU -- aka the "case
temperature."

All Socket-754, 939 and 940 systems now _honor_ the AMD processor
overheat/shutdown command.  AMD started mandating it as of about 2 years
ago on Socket-462, since all Athlon XP processors have been capable of
it.  The mainboard manufacturers were slow to change, just like with
mainboard-mounting heatsinks.  Luckily this is no longer the case with
all Socket-754, 939 and 940 mainboards I've seen..

On Wed, 2004-12-22 at 05:31, Terry Henderson wrote:
> It's on the AMD site, and I know it's rather cryptic [thier website],
> but it's there.

But no more cryptic than Intel's.  You have to hit the product
specification guides in _any_ case.  And if you self-assemble, you
should be hitting these things anyway -- to know _exactly_ what series
CPU you are getting.

Athlon 64 processors (non-FX/Opteron, both older and newer revisions):  
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/30430.pdf

Most of the Athlon 64s are rated for 65 or 70 degrees Celsium "case
temperature" which means the temperature outside the CPU -- like the
mainboard thermaresistor below the CPU.  I'm sure the other case
temperature will be _much_lower_ that right next to the CPU.  Aim for
the processors that are rated for 70 degrees Celsius, which means they
are the newer design -- yes, even though the speeds are higher.  ;->

You'll note most Athlon 64s are giving off 55-75W of thermal heat now. 
That's not too bad, and not much beyond the Athlon XP.  That's expected
because the Athlon XP and Athlon 64/FX/Opteron share about the same core
design (despite the 32 v. 64-bit differences, they are very similar
internally).

Compared to a Pentium 3, this is much greater.  But the Pentium 3 is
based on a much older core (designed for only 200-1000MHz, extended to
1500MHz with async techniques).  But compared to a Pentium 4, the Athlon
typically runs much cooler.  Especially the new Pentium 4 "Prescott"
design that can run as hot as 110W!  The Prescott is "going back to the
drawing board" as Intel has had a _design_failure_ in reaching 4GHz.

And if you are interested in older processor specs ...

Athlon XP Model 10 aka "Barton" 512KB and 256KB:  
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/26237.PDF
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/27375.pdf

Athlon XP Model 8 aka "Throughbred-A/B":
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25175.pdf

Athlon XP Model 6 aka "Palamino":  
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/24309.pdf


-- 
Bryan J. Smith                                    b.j.smith at ieee.org 
-------------------------------------------------------------------- 
Subtotal Cost of Ownership (SCO) for Windows being less than Linux
Total Cost of Ownership (TCO) assumes experts for the former, costly
retraining for the latter, omitted "software assurance" costs in 
compatible desktop OS/apps for the former, no free/legacy reuse for
latter, and no basic security, patch or downtime comparison at all.