[lug] more hardware opinions?

[Lee Woodworth]

D. Stimits wrote:
> It seems there are way more cpu types available now than just a few 
> years ago, and almost all of them have gone way down in price. I'm 
> especially noticing some opteron boards. I know the opterons work in 
> linux, and that they have both 32 bit and 64 bit instructions natively. 
> What I'm really curious about though is how opterons would compare to 
> something like the most recent pentiums, or the athlons? Does anyone 
> here have any experience or heard anything one way or another as to 
> where opterons, athlons, and newer Intel cpu's compare on the food chain?
The Athlon XPs are history -- not in production, replaced by the Sempron
line (32-bit). You may be able to find some XPs still out there but they
are likely to be expensive. Performance-wise, the XPs are supposed to be
faster than the Semprons (which are the cheap model line).

The AMD64s seem to be more expensive than the P4s w/ EMT64. The 64-bit
vs 32-bit doesn't appear to make a difference in many workloads. The biggest
difference will be how easily more than 4GB of RAM is handled. I have
an XP 3000 w/ 512K cache clocked at 2,16GHz and an AMD64 3000 w/ 512K
cache clocked at 2.0GHz. The XP has 512MB, the AMD64 1GB RAM. The AMD64
is running a 64-bit kernel with a 64-bit version of the openssl package.
The openssl speed command results were pretty much the same for both
except on one test (the AES encryption I think). The AMD64 was
nearly twice as fast for that one case.

A major area where the P4, the XP, AMD64 and Opterons differ is
the memory bus. The XP bus is slower than the P4's which is slower
than the AMD64s. The AMD64 has one hyper transport bus, while the
Opterons have more than one. It requires having enough DIMMs
to see the benefit of more than one hypertransport bus.

The last time I checked, the Opterons were much more expensive than
the AMD64s. If you go with an AMD64, be aware that the socket 754
version is being (or maybe already) phased out.