p4 v itinium

Richard Walsh rbw at ahpcrc.org
Fri May 17 06:40:23 PDT 2002

On  Fri May 17 04:15:19 2002, Ricky Rankin wrote:

>I am concerened who these would perform on a p4 compared to an
>Itanium, which can handle the memory.

The SPEC 2000 FP numbers comparing the Pentium 4 and Itanium 
(2000 MHz vs 800 MHz respetively) are roughly equal:

Itanium        701
Pentium 4      714

This is the mean of a suite of codes relative to their performance 
on an old Ultra Sparc 10 running at 300 MHz which rates 100. So both 
systems are about 7 times faster than the Sparc.  The IBM Power 4 at 
1300 MHz rates a 1169 for comparison, the best number on this benchmark.

The two numbers will/have improved with the faster clocked Pentium 4s 
with the larger on chip cache and  faster bus to memory, and the 1000 
MHz McKinley which should be available now. One thing to note about the 
IA64 systems is that they offer 4 FMA pipes at 32-bit precision.  Also, 
your compiler on the Pentium 4 should make good use of the SSE hardware 
(Intel's does). 

Another point of comparison for large, memory intensive operations
would be the stream triad MFLOP numbers.  These are:

Pentium 4	~185 MFLOPs (for 1.5 GHz system; sites data 
			     could use some more recent data points)

Itanium		~120 MFLOPs (again a bit old and should be 
			     substantially better with the McKinley
			     using HP's zx1 chip set if you
			     can get it.)

The Itanium suffers here from a weaker memory bus, but the new
McKinley should do better with the new motherboards from HP.

So if you require 4 GBytes of memory per node, I would expect the IA64 
systems to roughly equal the Pentium 4 at some additional cost. Other 
64-bit architectures to look at would be the IBM Power 4 and the Alpha 
EV6 and EV7 (expected to be release in Q4 2002).

Hope this helps,


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