Advanced Micro Devices Inc (AMD)

[chipguy]

Same way as P4 is just a x86 cpu with SSE2 extensions
that are, BTW, absolutely required to run it faster than
Athlon.

No kidding? The benefit of SSE2 is primarily DP FP SIMD
instructions. A P4/3.2C yields 1252 SPECfp_rate2k while
an XP 3200+ yields 873 SPECfp_rate2k. The P4 is 43% faster
as measured by SPECfp_base2k. Intel has disclosed that the
use of SSE2 instructions improves the SPECfp2k score of
the P4 by about 5%. This implies that even without SSE2
the P4 would still beat the Athlon by about 36%.

Perhaps your use of "absolutely required" above was a bit
overstated. :-P