Nicolas George spake:

> Stefan Viljoen  wrote in message <44cc7a88@news.povray.org>:
>> Would have been nice if it rendered twice as fast, though... but what is
>> the real spead increase factor (if any?) on a benchmark scene?
> 
> It is not a benchmark, but it is possible to make some estimate:
> 
> - 64-bit processors break compatibility with 32-bit processors, that
> enables
>   them to forget some bad conception problems of their ancestors, and thus
>   to run somewhat faster globally.
> 
> - Povray uses mostly floating-point arithmetic, to which the 64-bit
> quality
>   of the processor does not change anything. For arbitrary precision
>   integer arithmetics, like in asymmetric cryptography, on the other hand,
>   it changes a lot.
> 
> - 64-bit processor means bigger pointers, and therefore slower operations
>   when storing and fetching pointers to/from memory. Thus, operations on
>   complex data structures will be slower than they would have been on an
>   equivalent 32-bit processor.
> 
> All this, of course, applies in the common working domain of 32- and
> 64-bit processors. 64-bit processors allow to handle much more memory at
> once, thus allowing them either to work with subjects that a 32-bit
> processor just could not handle, or to do it in a much simpler -- and
> therefore faster -- way.

Given all everybody has said - why the heck use 64bit processors with Pov
-at all- then?

What I've gathered so far:

- They're slower, using bigger pointers that take longer to manage
- They don't give much benefit to PovRay - 32 bit processors already have
enough accuracy
- They don't have the capability (yet) of doubling the amount of memory you
can actually use, due to hardware limitations in memory management, so the
ability of adressing more memory is moot?

What's the point then? Where I live 64bit systems are incredibly expensive,
and given the thread I'm sure not making the investment of upgrading. Sure,
its naieve, stupid, shortsighted or whatever to think 64 versus 32 is
"twice" anything (my apologies for apparently severely offending people for
even thinking that) so why use them? If you're not going to be cracking
cyphers, and there is virtually no benefit at all to raytracing on the
things instead of on 32 bit systems?

-- 
Stefan Viljoen
Software Support Technician / Programmer
Polar Design Solutions

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