Opteron Vs. Athlon X2

[Peter Arremann]

On Monday 05 December 2005 22:42, Bryan J. Smith wrote:
> FYI, the new dual-core Opteron 165 and 175 are Socket-939.  They use
> unregistered DDR SDRAM, just like any other Socket-939 processor.
Please read the whole email before posting FYIs like that... I'm well aware of 
the opteron 1xx for the socket 939 as you see below. 

> > Not really that much. In fact, because of the slower memory timing of
> > socker 940 opterons (registered memory adds latency) the performance
> > improvements from the larger cache are mostly negated according to our
> > tests.
>
> Agreed, but if you're going with a Socket-939 Opteron 1xx, then that's
> not an issue.
>
> > No - Socket 940 (most opterons) and 939 (some 1xx opterons and Athlon64)
> > are not compatible. The 939 1xx opterons that are out now are nothing
> > more than a relabeled Athlon64 X2 anyway.
>
> Huh?  Not exactly true, especially since some are E5 and others are E6.
> And there _are_ the thermal differences.
They come off the same production line and the difference is the cpu 
identifier used when finalizing the packaging after the cpus have been 
binned. Thermal envelopes are determined by measuring the quality of the die 
and are therefore easily explained with more stringent requirements when 
selecting the die used. That is the same concept AMD uses for their HE 
models. 
 

> > On the other side, if you go for dual 2xx opterons and you pay extra for
> > a good board, you get a huge improvement on IO. Multiple PCI-X busses and
> > the like are nice to have on most servers but for a developers
> > workstation it doesn't really matter.
>
> As long as you don't need more than 100MBps in disk and network.
> Otherwise, PCI-X is still much better because most desktop mainboards
> only ship with PCIe x1 channels outside of video.
Why "in disk and network" ? We're talking workstation here, so its to assume 
that onboard controllers (pata or sata) are being used. In that case, the 
choice is pretty much down to Via and NVidia - both of which I thought bypass 
the pci bottleneck in their chipset designs? 

Peter.