Alain <ele### [at] netscapenet> wrote:
> It's not realy about speed, but about RAM access capacity.
> With the 32 bits version, there is an absolute limit of 4Gb for the amount of
> RAM available, more like 2 to 3 Gb due to various OS limitations.
> With the 64 bits version, that limit disapears, BUT, you also must be running a
> 64 bits OS on a 64 bits CPU, with enough RAM installed.
>
> This can come to a faster rendering IF you have a scene that need LOTS of space
> in memory (over 4Gb), have all the memory installed and can prevent the use of
> the swap file. Such a scene just CAN'T be rendered on a 32 bits system.
>
> Any gain in speed don't come from the 64 bits processing, but from the generaly
> more clock effecient 64 bits processors.
>
> --
> Alain
> -------------------------------------------------
> You know you've been raytracing too long when your idea of a complete computer
> is a fast CPU, lots of RAM, and a means of running POVray.
> Aaron Gage a.k.a Slartibartfast

I know it's been a long long time, but I just wanted to add to this conversation
that fact that the 64 bit processors also have several more registers than the
IA-32 counterparts.

So with 64 bit you get more memory access, and more registers on the "good"
side.  On the "bad" side is the fact that all pointers are now 8 bytes, which
may negatively affect your data cache performance.

--Keith Brafford

Post a reply to this message