Would adding RAM to 2009 imac improve performance

Since I upgraded to Mavericks from Snow Leopard, my 24 inch 2009 2.93 Ghz imac has been quite slow. It's slow to open up programs and slow in general.

Currently the imac only has the 4Gb of RAM that came as standard. Would upgrading to 8Gb be worth it? I can't afford a new machine at the moment.

Thanks for any advice - it's much appreciated.

PS. I regret (in some ways) not remaining on SL but I needed 10.9 to use an application.