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