* Use as little software as possible.
* Use software that does one thing well.
* Do not use software that does many things poorly.
I have a "good enough" workstation with 4GB of memory. No matter how much tweaking I do to eclipse.ini, Eclipse still crawls to an halt when I work on our large Java project... Alas, I can't just change it to VIM + command line svn. It would be a mess.
My reading of what he's saying with the three points is:
* Don't just go installing and using a bunch of stuff for the sake of it. Make everything justify it's existence on your machine and in your processes.
* Multiple individual tools which do things well are better than general tools which do many things badly.
Probably also worth distinguishing between amount of software and number of applications.
For instance, Eclipse may be just one application but it's a lot of software. It is admittedly a slightly abstract measurement but I think there would generally be broad agreement on the scale of most things.
In terms of your specific issue, it may be that 4Gb is not good enough as much as you'd like it to be. It will depend what else you're running, how big the project is, what it's doing and so on... Plus, Eclipse is a pretty chunky tool itself.
For future reference, while I didn't find a Scala forum post, I found the following (perhaps you referred to the first item):
http://blog.normation.com/2010/07/27/set-up-eclipse-workspac...
http://stackoverflow.com/questions/501718/can-i-use-a-ram-di...
http://stackoverflow.com/questions/1838018/optimize-use-of-r...
* Use as few workflows/tasks/'things' as possible.