Opteron Vs. Athlon X2

[Bill Broadley]

On Wed, Dec 07, 2005 at 12:53:30PM -0700, Maurice Hilarius wrote:
> > Does an Opteron dual-core give me any advantage over the Athlon X2
> > besides a bigger L2 cache?

Some of the X2s have 1/2 the cache of the opteron, some have the same
(1MB per core).

> ECC RAM capability, assuming you have a board and BIOS that also support
> that.

The Athlon 64 X2 supports ECC, at least the "AMD Athlon 64 X2 Dual Core
Product Sheet" (pub # 33425) claims it does.  Specifically double bit
detect and single bit correct.

> > Can I take an Opteron processor and drop it into my existing MSI
> > motherboard, or should I expect to buy a new motherboard also? If so,
> > what motherboard?
> >
> Doubtful

Dunno.  Keep in mind most opterons are 940 pin, only the newer
1xx's are 939 pins.  I've heard that sun was part of the influence.

The differences between 939 pin opterons and amd64's are from what
I can tell only clock speed and cache.  

> Depends on your needs.
> Opterons are meant for Workstations/small servers, hence the ECC support.

Careful here. 

S940 opterons require ECC registered memory.  S939s do not.  In general
you are much more likely to get full ECC (motherboard, cpu and bios)
compatibility with an opteron then you are in a amd64.  But that isn't
the CPUs fault.

S939 opterons and S939 amd64's use non-registered memory.  They support
ECC, but many motherboards seem not to support it.  On the ones I've
checked the manual nor bios mentioned ECC.  Additionally in other manuals
I've seen that ECC "works" but doesn't provide ECC functionality.

-- 
Bill Broadley
Computational Science and Engineering
UC Davis