On Wed, Oct 10, 2007 at 09:24:25AM -0500, Robert C Wittig wrote: | Siju George wrote: | | >I thought by running an amd64 kernel will get me twice the speed than | >an i386 on an amd64 machine since one is 64 bit processing and the | >other is just 32 bit :-( | > | | 64 bit processors (combined with 64 bit capable operating systems) have | the ability to address more RAM than 32 bit processors because 64^2 is a | much larger number than 32^2... lots more RAM addresses). | | This does not speed things up, though, until you run out of RAM, and | start having to access the swapfile. | | The processor's speed... MHz, GHz, etc., will determine how fast the | processor itself can process instructions.
Depending on your software, 64 bit processors can be quite a bit faster. If you're dealing with 64bit integers, using 64bit registers, etc., a lower clocked 64bit CPU might be faster than a 32bit CPU clocking at a higher rate. In short: There is no short answer. It depends on what you're doing. >From what Henning tells us (and what sounds logical to me), grabbing a ethernet frame from a NIC and putting it on another NIC doesn't really change much from 32bit to 64bit. Your compiler also comes into play. If that is more tuned towards a certain 32bit architecture (such as i386) than a certain 64bit arch (because it's less populair, such as sparc64 or hppa64 or mips64), this will impact your performance quite a bit. Cheers, Paul 'WEiRD' de Weerd -- >++++++++[<++++++++++>-]<+++++++.>+++[<------>-]<.>+++[<+ +++++++++++>-]<.>++[<------------>-]<+.--------------.[-] http://www.weirdnet.nl/ [demime 1.01d removed an attachment of type application/pgp-signature]