On 11.11.2009 17:44, Dieter Plaetinck wrote: > On Wed, 11 Nov 2009 17:18:12 +0100 > Sven-Hendrik Haase <sh@xxxxxxxxxxxxx> wrote: > > >> You will probably see the >> opposite of what you saw in the VMs. Especially for video encoding, >> x86_64 will be noticeably faster. >> > > why is that? > > I'm not a CPU expert and I got the figures by empirically testing just what Sergey did, but in a real machine (Q6600). 64bit CPU have 64bit registers which is what I suppose makes them work a lot faster for stuff like video encoding, 3d rendering and encryption. Somebody did a quick benchmark on this actually: http://bingouv.blogspot.com/2008/08/desktop-linux-performance-comparison32.html The results here would confirm it: http://www.phoronix.com/scan.php?page=article&item=998&num=3 So it seems that x86_64 is usually a tad faster than i686 unless you really try to make use of the architecture's advantages in which case (according to wikipedia) it could become a lot faster. Actually, why not just do some testing yourself and see what the results are? 4-5 years ago, x86_64 computing was rather immature and lots of optimizing assembly code for video encoders wasn't yet ported. -- Sven-Hendrik
