Sudo Purge

comment was already stated

The purge command flushes the I/O cache, seeking to make the I/O performance similar to that of the bootstrap environment.

Typical operating system I/O cache design usually seeks to use much of the "free" memory to try to avoid I/O given its comparatively glacial performance. Any "free" memory is really just wasted memory, after all. If the physical memory becomes needed by an application, the cache should be reduced amd the memory reallocated to the application. This reallocation does mean that performance drops as the cache hit rates drop as the cache is reduced in size.

Put another way, I wouldn't expect much benefit from flushing the cache, and I might expect aggregate performance to drop.

A local test shows the sudo purge command does work on Mavericks, so I'd wonder if there's something odd about your default PATH setting (try sudo echo $PATH ). According to locate, the purge executable file is in the /usr/sbin directory, so that will need to be in your PATH. Alternatively, try the sudo /usr/sbin/purge command.)

But again, using otherwise unoccupied (wasted) free memory as an I/O cache usually isn't even a trade-off.

I was under the impression that 'purge' was installed as a side effect of installing Xcode. But it has been so long since I've had a system without Xcode I do not have a system to check my assumption.