[Beowulf] Supplier for 8-way Opteron Systems?

[Mark Hahn]

> Can anyone recommend a vendor for 8-way Opteron servers?

*are* there any?  I presume AMD has made such machines,
but I certainly haven't seen anyone selling them.  this has been
a grave disappointment to many, many potential customers,
and it's quite puzzling that AMD hasn't managed this achievement.

if you look at spec*rate scaling for 1,2,4-way opterons, it seems 
like AMD's HT and per-CPU memory would provide really quite good 
further scaling.  I'm beginning to suspect that AMD built a few,
and found that the coherence traffic was crippling, and has gone 
off to twiddle things.  personally, I'd hope that they add directory-
based coherence, since that would clearly scale very nicely (see Altix!).
if that wasn't the case, AMD's not giving much signs of trying to 
address this - perhaps the bump to 1 GHz HT will help, but it's not much.
worst of all, perhaps they're trusting dual-core to "solve" the problem,
and that would be almost pitiful, since the people who are most excited
about 8-way Opterons are exactly the ones who do not have good cache re-use.

I mentioned AMD's extremely steep Opteron pricing scheme 

	http://sharcnet.mcmaster.ca/~hahn/amdprices.png

to a significant AMD marketing person recently.  I pointed out that 4-ways
are fairly attractive, even though they're a lot more than twice the cost of
dual systems.  his response was that AMD wants and needs the much higher 
margins that have traditionally applied to higher-end SMP.  he didn't seem 
to care about the fact that markets are elastic, and AMD's current policy 
is forcing customers to avoid 4x machines, or even go to uniprocessors,
not to mention the complete lack of 8x machines to put 8xx processors into.

regards, mark hahn.