About 18 months ago I upgraded my workstation from a Pentium III 850 MHz system to an Intel Core 2 Duo (2.4 GHz) system.  In addition to the giant CPU upgrade (triple the MHz and dual-core) I also doubled the RAM from 2 GB to 4 GB.

With 2 GB, my system was swapping quite often, because Firefox and Thunderbird are memory hogs, because I run Firefox with 30+ tabs constantly, and because I always have many, many xterms, gFTPs, and text editors (Adie) running.  With the upgrade to 4 GB of RAM, my system would run swap-free for a few days, which was a beautiful thing.

But inevitably FF and TBird’s memory usage would creep up, and the number of xterms/gFTPs/editors I was running would steadily increase as my system was up for weeks and months on end.  So after the first few days of uptime, the swap would slowly start being utilized again.

Well a couple weeks ago I finally got around to switching my system from the 32-bit version of Ubuntu to the 64-bit version.  I used the release of Hardy Heron as an excuse to wipe the system clean (which had been upgraded from Dapper to Edgy to Feisty to Gutsy) and do a new install using the amd64 ISO image instead of the i386 image.

Because of limitations inherent in running a 32-bit operating system, the maximum addressable RAM is something like 3.3 GB, so even though I’d had 4 GB installed, I could only use 3281 MB of it (as shown by the "free -m" command).  After installing 64-bit Hardy Heron, though, the available RAM jumped to 3887, over 600 MB more!  Between that and the fact that Hardy includes Firefox 3 (beta), which has a smaller memory footprint than Firefox 2, my system is now swap-free all the time.