On Mon, 2008-02-04 at 14:36 -0600, Frank Cox wrote: > On Mon, 04 Feb 2008 06:01:11 -0700 > Warren Young <warren at etr-usa.com> wrote: > > > If you don't have enough RAM to need 64-bit addressing, you're just > > slowing the system down, making it deal with larger addresses for no > > benefit. > > While my Centos machines are all running 32-bit at the moment, I have Fedora > 8/x86_64 on my main desktop computer (this one) and there is a noticeable > speed increase when scrolling a large Scribus document, compared to when I had > Fedora 7/i386 on this same computer. I have had the same experience. Until I looked for the presence of a 64 bit machine I installed a 32 bit os on everything. I found the sales descriptors of computer stores unreliable as to what was 32 bit and what was 64 bit. If cat /proc/cpuinfo | grep " lm " truly identifies 64 bit machines we had some 64 bit CPU's that were not identified. I experimented a little to see if putting a 64 os on these would improve desktop responsiveness and my gross perception was that there was an improvement. Most of the time these desktop units had less than 2 gigs of RAM. However, I may have been seduced by positive expectations. Does anyone know of a way to really determine if this is significant. I recently installed CentOS-5.0-i386 for a mail server that was supposed to be 32 bit, but when I checked it after the install I found it was 64 bit. I decided to take the time to reinstall CentOS-5.0-x86_64. This machine came Vista and was sold to us from Fry's as a 32 bit refurbished Compaq. So being able to tell what is a 32 and 64 cpu and whether running a 32 bit or 64 bit os on a small mail server is worth while might be helpful. Any thoughts? Greg