1951FDG has released a new version (1.2.0) of SixtyFour (http://getsixtyfour.com/), a memory optimizer for Mac OS X.
SixtyFour is designed to help Mac users keep their older Macs running longer and better, even when today’s apps are 64-bit and require much more RAM than Macs of just a few years ago. It facilitates the setting of a preference to force a 64-bit app to open in 32-bit mode.
SixtyFour is compatible with any 64-bit-capable Mac running Mac OS X 10.5 or higher (including Mac OS X 10.9 Mavericks). It costs US$4.99.