Hi,

I am trying out the Povray 3.6 beta 6 on 2 machine and I noticed an
performance difference when rendering quite a complex scene (very large
meshes involved).

Machine 1)
    Pentium II 333 MHz, Win98, 256M ram (Virtual memory 128M)
Machine 2)
    Pentium III 500 MHz, WinNT 4.0 sp6, 128M ram (Virtual memory 256M).

The issue being that Machine 1, is much faster than Machine 2, even
though M2 has the better and faster CPU. I know it could be the memory
difference, but not such a performance degradation as observed. When
rendering the same image the Win98 can render at 1280x1024 AA 0.3 and
still beat the WinNT rendering at 800x600 AA 0.3.

Has there been any benchmark comparison between versions of windows
done?

I'll happily make the scene available for test purposes.

Chris.

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In article <3BD5C089.7FAD234E@dev.tivoli.com> , Chris Fieldhouse 
<cfi### [at] devtivolicom>  wrote:

> I know it could be the memory
> difference, but not such a performance degradation as observed.

Yes, because NT needs more memory than Windows 95/98/ME.  Then there is less
left for POV-Ray and you get the performance problems.  It is important to
keep in mind that certain portion of memory cannot be swapped to disk, so
even if your scene takes much less than 128 MB you run into problems.
Upgrade the NT system with more memory and the problem will at least be
reduced.  Of course there can be millions of other configuration reasons why
POV-Ray is slower on your NT system.

There surely isn't an internal switch in POV that makes it run slower when
the system is NT ;-)

    Thorsten

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Wasn't it Chris Fieldhouse who wrote:
>Hi,
>
>I am trying out the Povray 3.6 beta 6 on 2 machine and I noticed an
>performance difference when rendering quite a complex scene (very large
>meshes involved).
>
>Machine 1)
>    Pentium II 333 MHz, Win98, 256M ram (Virtual memory 128M)
>Machine 2)
>    Pentium III 500 MHz, WinNT 4.0 sp6, 128M ram (Virtual memory 256M).
>
>The issue being that Machine 1, is much faster than Machine 2, even
>though M2 has the better and faster CPU. I know it could be the memory
>difference, but not such a performance degradation as observed. When
>rendering the same image the Win98 can render at 1280x1024 AA 0.3 and
>still beat the WinNT rendering at 800x600 AA 0.3.

On machine I, more of the POV memory space fits in the available real
memory (perhaps it all fits). On machine II, Windows has to swap bits of
POV in and out of virtual memory far more frequently because less of it
fits in real memory at any instant. If you watch your hard disk light,
you may see that your disk is constantly active on machine II. Disk
accesses are extremely slow compared to memory accesses, and the
rendering speed falls dramatically when there's a lot of swapping
required.

What are the speeds like if you render simple scenes that are small
enough to fit into the available memory of both machines?

-- 
Mike Williams
Gentleman of Leisure

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