How do I stop my external hard drive from using all my RAM? I'm running OSX Mavericks, and have an external 500Gb HD connected via firewire.

I have 24GB's of RAM, and fairly often my RAM usage will spike to 23.95 GBs in use and literally leave me with only 50 MB of RAM, or less, usable.

I know it's my external drive because when I eject it the memory usage goes back to normal, which is about 5GB used. 

How do I stop the drive from using so much memory?
The external drive by itself won't use RAM. Check the processes that are running in Activity Monitor — you can sort by RAM usage.