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TC schrieb:
> Could you run the benchmark with 32-bit PoyRay binaries? It should not take
> too much time to download - and less then two minutes for you to run. ;-)
Not really:
- The 32-bit beta won't install unless I uninstall the 64-bit version
first (which, as you can guess, I'm rather reluctant to do ;-))
- Although I compile patched versions of beta.33 almost daily, and it
wouldn't be a big deal to just run a "non-installed" 32-bit binary once
I got it built, I never tried before on my 64-bit machine. So, for
instance, I didn't have 32-bit boost libraries ready.
Well, you can see that I'm using past tense here, so obviously I went
that extra mile ;-)
Note however that the results must be used with caution:
- Windows XP x64 is a native 64-bit operating system; I guess any 32-bit
application will suffer some slowdown due to overhead for switching
between 32-bit and 64-bit every time OS functions are called (such as
mutexing and other multithreading related stuff, file access, etc). So
part of the speed difference could indicate not an advantage of 64 bit,
but a disadvantage of running a 32-bit app on a 64-bit OS.
- I found that the SSE version didn't compile in Visual Studio 2005 for
some obscure optimization-related issue, so I had to turn off some
optimization option. (The non-SSE version does compile "as is", but
would of course distort the results because the 64-bit version always
uses SSE.)
I also ran a "home-brewn" 64-bit build, to make sure I'm not comparing
compilers (official releases are built with Visual Studio 2008) or the
effect of some experimental patches presently in my working code.
The results I got are as follows:
32-bit: 150 s
32-bit SSE: 123 s
64-bit: 74 s
So at least it can be concluded that using the 64-bit binary /does/ give
a significant advantage /when running a 64-bit OS anway/.
Given the impressive observed difference, I also /think/ that the
overhead from running a 32-bit app on a 64-bit OS and/or lack of some
optimization can't possibly account for all of it, and that a "64-64"
system indeed gives an advantage over a "32-32" system. However, I can't
guarantee.
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