intel icc 8.1 compiler performs poorly in nbench on my PC

[borism]

I've got an AthlonXP "2000+". I recently installed icc8.1.032 and I am very disappointed. On my system it is slower than gcc3.4.4 (with glibc 2.3.5).
I untarred nbench manually so that I could play with the settings in the make file and run a few benchmarks.
I started off with compiling with "default" -O2, that produced a larger binary and faster code than my default gcc -O2. Then I read the man pages. It turns out that icc enables unsafe math optimisations and loop unrolling by default. Ouch. That explains the large binary. As a matter of fact, even with -Os intel binary is larger than gcc's with -O2. So in space-speed tradeoff (so much talked about in CFLAGS threads) gcc definitely holds its own.
So I decided to get the best out of both compilers as far as speed is concerned.
For Intel I enabled function inlining (-Ob2) and inter-procedure optimisations as well as generated code for P3 (to include SSE) and tune it to P4 (Athlon-XP generation). Loop unrolling, fast math and frame pointer omission are enabled by default.
For gcc I enabled fast maths, loop unrolling, and frame pointer omission. -O3 enables function inlining. To be fair to intel compiler I optimised for P3 and tuned to P4.

So, apples to apples as much as possible.

Here are the results:

[virtual]

Hi,

Maybe because you do not have an Intel processor but one from AMD. I know they are compatible but their internal architectures differ
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The roots of education are bitter but it's fruit is sweet.

[borism]

[madmango]

If you read the charges that AMD is bringing against Intel, they claim that icc specifically uses a poorly-optimized code path when the code is compiled on an AMD processor.
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