Mavericks Using Up All Available Memory I upgraded to Mac OS X Mavericks. I thought that Mavericks was supposed to use memory more efficiently. It appears that the OS has memory allocation problems. My computer is using up 99.99% of my memory even when it's just sitting idle, turning my iMac into a paperweight. My computer lags and freezes even when it's not doing anything.

Is there anything that I can do, besides upgrading my physical memory?
Try opening Terminal and typing in: 
sudo purge

or you can try Memory Clean at 
https://itunes.apple.com/us/app/memory-clean/id451444120?mt=12

BTW: It would be beneficial to post screenshots or use EtreCheck (created by an Apple Support Community User) and copy and paste the results. Etrecheck can be found at http://www.etresoft.com/etrecheck