UP2000 vs DS10 for beowulf?

[Greg Lindahl]

> I am looking at two different configurations of 600Mhz, 2M cache alpha
> 21264w
>    6*2 processor  UP2000, 512M RAM
> or
>  12*1 processor DS10L 256M RAM

Christoph's answer was very good, but I would add that you might want to
consider the other products in this space, namely the DS20E and the UP1100.
The DS20E has DDR Sram cache, which is a 10% to 30% boost to some codes.
You'll have to ask API when they plan on releasing DDR Sram, I believe it's
fairly soon. The UP1100 has an AMD chipset so has significantly slower
stream numbers, but it's cheap, and your codes might not be sensitive to
stream bandwidths.

You might also prefer the DS10 over the DS10L, since it costs money to get
that 1U package.

> One thing that is a bit worrying is having two processors talking
> through one PCI bus to the high speed network.

I have not seen a problem with that. On a wide range of codes, I think the
bigger factor is memory bandwidth.

> Does anyone have two processor stream numbers for
> UP2000s?

Around 1300, or 1.1X-1.2X the single processor number. The DS20E is only
slightly higher. The ES40 gets 2.5X with 4 CPUs, not so great. That's why
I'm still a fan of single cpu machines, myself.

-- g