[Beowulf] Intel Quad-Core or AMD Opteron

Vincent Diepeveen diep at xs4all.nl
Fri Aug 24 09:37:27 EDT 2007


Even worse,

Does SSE2 code of intel not by default in th eintel primitives have an 'if
then else' that at opteron it runs without using SIMD?

But apart from that, SIMD at oldie K8 is very slow compared to core2,
though not a factor 2. Barcelona for well optimized code should have an
IPC in SIMD of up to 40+% faster i guess than core2.

So only 2 questions are when they release and especially at *what* price
for the 4 socket mainboards.

A 16 core barcelona machine with 4 DDR2 memory controllers might be a very
mighty system for all kind of applications that need shared memory to
scale well.

When releasing Barcelona core within a few months from now, AMD has a huge
lead over intel with respect to 4 core cpu's, as it seems to me.

I feel personally intels choice of CPU design using small tiny L1 caches
from performance viewpoint is a catastrophic one. If there is just ONE
competitor for an intel chip that manages to clock a cpu nearly at the
same clock like intel and with the same number of cores, then intel
usually gets totally outperformed. Now that intel & AMD produce
cpu's at the same type of machines their cpu's, it seems to me
that AMD will in general outperform intel.

Comparing the 2006 core2 with a 2003 release is not a very fair
compare IMHO.

We can definitely conclude that intel managed to produce their new
generation cpu ( core2) more than 1 year sooner than AMD did do, using a
simple trick, namely glueing 2 dual core chips together.

In the meantime i keep wondering more and more about intel not having an
equivalent on the market for AMD's hypertransport.

For highend, when buying multiple socket nodes, it is hard to see intel as
an alternative to barcelona core driven machines, as it doesn't have any
form of load balancing thanks to having just 1 memory controller for all
cores.

Most interesting for scientists might be buying a few nodes with some
double rail network and each node consisting out of 4 socket AMD machines
quadcore. Initially now perhaps 2Ghz. Then in end 2008 you can
upgrade the cpu's to 3+ Ghz.

When also putting a lot of RAM onto such AMD machine, then
such a node of course also totally annihilates power6, even before power6
gets taken into production, against a fraction of the price of a power6
node.

The advantage of using 4 socket machines for a cluster/supercomputer is
obviously the fact that the network costs form a smaller part of the total
solution, meanwhile keeping the total number of nodes limited.

A few nodes you could arguably use 8 socket solutions for, not to scale up
to more cores, as most software can't handle such bad memory latencies,
but it might be you could even outgun power6 in terms of total memory a
node.

What is the amount of ram that power6 supports versus the 8 socket AMD
solutions?

Best Regards,
Vincent



On Fri, 24 Aug 2007, Toon Knapen wrote:

> > I understand that, when comparing Quad-Core Xeons with Opterons,
> > people focus on the scability issues of the different multi core
> > architectures, but we've run some benchmarks on both and the thing
> > that at the time surprised me the most was that if your application
> > makes much use of the functions provided by Intel Math Kernel Library,
> > a single Xeon core (e.g Clovertown) can be up to twice as fast as a
> > single Opteron core.
>
>
> You are comparing Intel MKL on Xeon with what exactly on Opteron? Intel
> MKL on Opteron is certainly not optimal. I hope you compared to GotoBLAS
> on Opteron.
>
> t
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