CPU Choices

[n.gregory at garageflowers.co.uk]

(sorry if this gets posted twice)
Hello,
I am doing some research into the configuration of a 32 1U node Beowulf cluster 
and have a question regarding CPU configuration.

The current choice is between Intel P4s as Itaniums seem a little bleeding edge at 
the moment, or the latest AMD chips.

AMD seem to be getting a impressive performance for the price, but I?m a little 
concerned about the lack of mature multiprocessor chipsets and their heat issues.

Intel on the other-hand have the MP chipsets but seem to be falling down with 
current lack of (non-commercial ) complier that support MMX and SSE, and the 
whole issue of Rambus Vs DDR memory.

I would be grateful for any insight into a choice of CPU and its configuration in 
terms of price/performance/expandability, or any other factor I should be 
considering.

Thanks
Nick