Whenever I change floors or enter/exit cutscenes, my game always freezes for around 5 seconds. Loading times are also much longer than usual.

 

I'm using OS X Mavericks using OpenGL mode (only option available on this computer). Anything I can do to get rid of this freezing thing?

Are you using the client or a browser?

 

Java on macs is a major pita and running it in browsers makes runescape rather unstable, whilst the client will run much more reliably.

I'm using the client. I still freeze for long periods of time.

Then the options are turning down graphics or getting better internet or getting better computer.