How to Stop your Mac Running Slow #OSX
I stumbled across this tip a few hours after struggling with my Mac running painfully slow after trying to load and manipulate a 1.5Gb SQL file. I knew it was a memory problem, but had no way to resolve it easily without rebooting all the time. Talk about using a sledgehammer to crack nuts.
The tool you need is TERMINAL. It can be run from UTILITIES on your Mac via the Dock.
The command you need to run at the command line after you open TERMINAL is simply PURGE
This command takes a minute or so to run (depending on your Mac) and will make it relatively unresponsive. You may even get an error as I did but this is part of the magic.
What PURGE does is tell each running process to free up any RAM (memory) it is hanging on to unnecessarily. And that goes for any RAM which may not have been freed when applications were closed. By running a PURGE you can free up the necessary memory and get everything running smoothly again without needing to reboot.