sevendy schrieb:

>                  trace                        Case 1                   Case  2
>                 threads  CPU(approx.)  photons       no photons       no photons
> 
> 3.6.2 64bit                 13%           99             31              158
> 
> 3.6.2 32bit,                13%          209             71              160
>     SSE2
> 
> 3.7 b36 64bit      1        13%       119(119)        36(36)           154(154)
>                    4        51%        48(159)        13(51)            53(208)
>                    8       100%        37(214)         9(66)            35(270)
> 
> 3.7 b36 32bit      8       100%        39(228)        10(70)            41(310)


To me, these figures are evidence that...

(1) with 3.7, the 64-bit version has a slight speed benefit over the 
32-bit version (but not much), which appears to me to make sense, 
provided that the 32-bit version uses SSE2;

(2) the 64-bit version of 3.7 is typically slightly less CPU-efficient 
(as can be seen when running on a single thread) than that of 3.6, which 
makes sense given that 3.7 needs some overhead to make sure that it can 
make use of multiple cores (or CPUs);

(3) the 32-bit SSE2 version of 3.6 is exceptionally slow with photons.

 From my seat, only (3) opens up questions. My first guess would be that 
3.6.2 32-bit SSE2 is compiled differently than 3.7.b36 32-bit - possibly 
due to a different compiler, though I'm not sure about that. Would you 
mind posting the exact version info (including platform and compiler 
identifiers) for each of the POV-Ray versions report when started? You 
should find it in the Messages pane, where it will output something like 
this:

-------------
Persistence of Vision Raytracer(tm) for Windows.
POV-Ray for Windows is part of the POV-Ray(tm) suite of programs.
   This is version 3.7.0.beta.34.msvc8.win64.
[...]
-------------

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