On 10/30/07, Aaron Kulkis <[EMAIL PROTECTED]> wrote: > Greg Freemyer wrote: > > On 10/30/07, Aaron Kulkis <[EMAIL PROTECTED]> wrote: > >> Robert Lewis wrote: > >>> I recently bought a 64 bit machine and have 10.3 loaded . It seems very > >>> fast. > >>> > >>> I am trying to appraise if the advantages of having some software not work > >>> because of driver issues is worth it. > >>> > >>> Has anyone run benchmarks on an identical system with 32 bit vrs 64 bit? > >>> > >>> Do we have a list of software that is known not to work on 64-bit? > >>> Any defined group tracking this and championing gettin the remainder > >>> fixed. > >>> > >>> I know this is a generalized question but I am just trying to appraise > >>> the gain vrs pain of deciding to stay with 64-bit ? > >> Most data isn't 64-bit. In fact, a large chunk of it > >> is still 16-bit, and even 8 bit (ASCII text, for example). > >> > >> Most of the speed increase you are seeing is from: > >> > >> 1) the faster clock speed of your new CPU compared > >> to the last one you had. > >> > >> 2) wider data buses into and out of the on-chip cache. > >> > >> 3) floating point operations (where applicable). > >> > >> You won't see a significant difference between > >> 32-bit and 64-bit system performance until you > >> are running some software which uses lots of > >> 64-bit integers, or is very intensive in > >> floating-point operations. > >> > > > > Surprisingly (to me at least) we are seeing a speed improvement with a > > specialized version of dd (dcfldd) going against raw disks. > > > > Why is it surprising that dd (which just moves large > chunks of data) would be improved by a movement from > 4-byte natural word size to 8-byte natural word size? > > That's like being surprised that thicker pipes can > move more gallons of water per hour.
Because everyone knows that the disk drive/SATA-bus/controller/PCI-bus/DMA are the limiting factors in raw dd speed, so who cares how the kernel/app are compiled. And my tests were with a PCI-bus controller. With a PCI-Express controller the 32-bit/64-bit issue for kernel/userland is likely even more important. Greg -- Greg Freemyer Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
