Regarding the -O5 switch, I tried compiling with that, but it caused the
compiler itself to crash.
I will try another run with your recommendations.

"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3f94e5b8$1@news.povray.org...
> In article <3f94a116$1@news.povray.org> , "Jenna Olson"
> <wan### [at] comcastnet> wrote:
>
> > POV Ray compiled with IBM's xlC V6.0 BETA compiler
> > (switches -qarch=ppc970 -qtune=ppc970 -qalign=natural -O3)
>
> Note that -O3 is _not_ the maximum optimisation setting for IBMs compiler.
> The maximum is -O5.  Also note that the default architecture/tuning will
be
> automatically selected to be correct for the architecture you are running
> on, so if you compile on the G5, no need to tell the compiler to optimise
> for it.  Also, you shouldn't be forcing unsuitable structure alignment on
> the compiler, leaving it at the default for the core code files will be
> best.
>
> In any case, make sure you specify -qaltivec, -qnostrict, qfloat=nonans,
> -qignerrno .  ALso, you may want to try profile guided optimisations on
> texture.c .
>
> > POV Ray compiled with gcc3.3 as part of fink distribution (no
> > optimizations):
>
> I think there is something wrong with these results if the compiler is
> indeed gcc.  Most likely the cause is that the ppc970 option (instead of
the
> ppcv option) for xlc just like the mpowerpc64 option for gcc generates 64
> bit code rather than 32 bit code.  Hence, with a heavily memory dependent
> program like POV-Ray, you will always see a significant loss of
performance
> when generating 64 bit code, especially with the plain 3.5 source code
(but
> that is another story).
>
>     Thorsten
>
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: tho### [at] trfde
>
> Visit POV-Ray on the web: http://mac.povray.org

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