AM2, X2, Opteron, or Opteron Socket F?

[Bill Broadley]

On Sat, Aug 19, 2006 at 09:52:52PM -0400, Robert L. Cochran wrote:
> I recently gave my trusty, rock solid Athlon 64 X2 4400+ system to my wife 
> (long story there, but it had to be done.) That leaves me with my 
> not-so-trusty laptop and a searing desire to build a new system.
> 
> My problem is deciding on a processor and motherboard.
> 
> At first, I liked Intel Core 2 Duo, but the motherboard selection doesn't 
> seem great and it is very pricy.

I'm in a similar situation, indeed the Intel Core Duo seems to be 
fairly expensive and less available then the AM2 systems.  On the AM2
side there's quite a selection of reasonably priced motherboards.

> I'm also confused by the advantages of Socket F, socket 940 (which I know 
> allows DDR2 memory), and the advantages of Opterons over Athlon 64s or 
> Athlon 64 X2. Or vice versa.

Rev F opterons or AM2 amd64's both differ primarily in that:
* They support DDR2 memory
* They have hardware support for virtualization.

> I need to do some heavy, heavy database programming and website building in 
> the next 2 years. I want quick ethernet controllers. I'll be working mainly 
> on a Linux platform, Fedora Core or possibly Red Hat Enterprise Linux.

You didn't mention a budget, certainly a dual socket/dual memory bus
machine will have substantially more CPU cycles and memory bandwidth
available.  If your database is disk limited the extra cycles
won't help at all.

> What AMD processor and motherboard would work best for me? Should I focus 
> on Opterons?

Opterons are more conservative, they receive more testing, although they
share almost 100% of the transistors with the amd64's.  For instance
the am2 chips support DDR2-800 MHz, while the opterons support ddr2-667.
Although that maybe more than DDR2-800 ECC registered dimms are hard
to find.

ECC memory is easier to get on the opteron, and opteron supporting
motherboards are the rule, not the exception.  The line is rather blurry
though.  For instance some motherboards accept amd64's and opteron 1xx's.

I'm not sure if amd is going to do an opteron 1xx rev f, they didn't
announce them and their pricing with the rest of the rev f's.

> One last note -- my old system has an Asrock DualSATA-939 motherboard 
> running the 2.20 BIOS. I took out the old ATI 9700 All-In-Wonder (AGP) 
> video card and put a BFG GeForce 7600 GT OC in the PCI Express slot. It 
> works great and powers my wife's 24" flat panel monitor at 1920 X 1200 
> resolution.

I'm very happy with the 6600GT and 7600GT's I've used, they take
significantly less power than the higher end cards while still delivering
pretty good 2d/3d performance.  Often the AGP versions require an extra
power (to run the bridge chip) but usually the PCI-e versions do not.

There's no real wrong choices to be made, personally I'm likely to get
a x2 around 2.2 GHz.  Cheap, fast, dual core, good enough for me.

The intel core 2's to give you more performance per MHz in most cases,
but the motherboards tend to be cost more, as does the CPU.  Be careful
about the DDR-2 memory you buy with a intel core 2.  I've seen benchmarks
that indicate that matching the FSB and the memory speed is faster than
buying faster ram.  I.e. if you get a 1066 MHz FSB get ddr2-533 (not 667
or 800), if you get a 1333 MHz FSB get DDR2-667 (not 533 or 800).

-- 
Bill Broadley
Computational Science and Engineering
UC Davis