fab wrote:

> AFAIK 4.0 was the first with a support for the new "core". The next (4.1
> probably) will be focused on optimisation, 4.0 is just for testing the
> new core and permit developpers to port the code without waiting a
> version with real advantages.
> I've seen some kind of benchmark that show C++ is faster with 4.0, maybe
> this is why people think 4.0 is faster.

My favourite compiler benchmark is a program called Glucas
(http://www.oxixares.com/glucas/), which is an FP-intensive
program.  Here's the run times for the small built-in self
test on a 2.4GHz Xeon, in order of fastest to slowest.

icc 7.0                 418.493u 0.379s  6:59.11 99.9%
icc 8.0                 428.591u 0.429s  7:09.18 99.9%
gcc 3.4.2               471.135u 0.389s  7:51.74 99.9%
gcc 3.4.0               477.925u 0.339s  7:58.39 99.9%
gcc 4.0.0 exp 20041206  495.001u 0.179s  8:15.39 99.9%
gcc 4.0.0 exp 20041006  500.106u 0.249s  8:20.52 99.9%
gcc 4.1.0 exp 20051026  522.606u 0.399s  8:43.15 99.9%
gcc 3.3.4               589.195u 0.189s  9:49.50 99.9%
gcc 3.3.3               596.945u 0.299s  9:57.43 99.9%
gcc 3.5.0 exp 20040610  599.820u 0.369s 10:00.38 99.9%

These were all built with -O3 {-mcpu,-mtune,-march}=pentium4
icc is the Intel C++ Compiler for Linux.

Interesting that in the twelve-odd months between the 4.0.0
and 4.1.0 compilers gcc has slowed down for this particular test,
and is still a reasonable way behind the 3.4 series compilers.

Simon.
--
Simon Burge                           <simonb@wasabisystems.com>
NetBSD Support and Service:        http://www.wasabisystems.com/