I have been wondering about this myself for a while. For many people, a Dreamhost PS is going to be the first private server they have ever dealt with.
If you’re on a budget, chances are you will max out the available resources on your PS at one time or another. Your server will go unresponsive. Dreamhost will tell you that the only way to correct this, is to “increase your maximum resources,” or to restart your server. In some cases, neither of these options will help.
I had to waist a couple hours with support in order to get a hold of the following link. The dreamhost optimization guide will guide you through the steps you need to hunt down the problem source, fix it, and maybe even speed your little PS up.