Not necessarily. It can take a long time to load a large project, including any Rails applications. A typical Rails application can take about 30 seconds to load (that's any time you run a Rake task, launch a server, run unit tests, etc) and unit test runs can typically take a few minutes, often times more than 10 minutes for large applications. If you use a test server, such as Spork, the load time largely goes away for running your tests, but there's still a few seconds of startup time. Just because a language doesn't have an explicit "compile" step doesn't mean its void of compiling-related problems.