Virtual machine performance is in no hell comparable to real machine performance, not even for comparing between each other. Current VM implementations generally run a lot faster on i686 guests because that's what they have been optimized for mainly. I always found my x86_64 VMs to be slower than i686 so this would go in hand with your own observations. If you want to make a serious comparison, set up two fresh chroots at least. Better yet, set up two partitions and do the tests using a native kernel as well. You will probably see the opposite of what you saw in the VMs. Especially for video encoding, x86_64 will be noticeably faster. -- Sven-Hendrik On 11.11.2009 17:11, Sergey Manucharian wrote: > Hi folks, > > The similar question most probably has been discussed many times, but I > really cannot find a clear answer. There are some obvious thinks like > 64-bit addressing, but how about math calculations performance? > > I've set up two identical virtual machines in vbox - one with Arch > x86_64 and another with Arch i686. I ran mencoder in both over the same > video and got the following figures: > > x86_64: 43 sec > i686: 34 sec > > which make x86_64 not so impressive ;) > > Some time ago I read an article at AMD web site, they suggested using > their math libs for writing programs instead of standard ones. In such > a case a program with complex math involved can performs much better > (personally I haven't tried). > > I'm just curious about other people's opinions on this subject. > > Cheers, > Sergey > > >
