> [...]
> 
> GCC 3.3.1 with -m32 -mcpu=k8 -msse2
>   3:26
> GCC 3.3.1 with -m64 -mcpu=k8 -msse2
>   2:59
> 
> GCC 3.4.0 with -m32 -mcpu=k8 -msse2
>   3:08
> GCC 3.4.0 with -m64 -mcpu=k8 -msse2
>   2:47

That either confirms what Warp said, that the processor is less 
efficient for 32bit code by design, or - if these times are indeed 
accurate enough - that gcc AMD64 specific optimizations were subject to 
significant changes recently.  Also note that you should use -march=k8 

and not only -mcpu (which should be replaced by -mtune with gcc 3.4 anywa
y).

And you should better use the benchmark scene to test, it will give more 

accurate time comparisons.  Also it would be important to test with a 
somewhat larger scene (benchmark.pov is not very large either) how the 
effect of the higher memory requirements for 64bit pointers etc. 
influences performance.

Christoph

-- 
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HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 21 Mar. 2004 _____./\/^>_*_<^\/\.______

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