System configuration
I'm working with a MacBook 2,16 GHz (13" white with the max. 3 GB RAM from about 2007) and "Snowleopard" OS 10.6.8.
The problem: performance
After a while, the MacBook becomes incredibly slow and unresponsive, because Safari and the Safari Web Content process use all available RAM.
At the moment, e. g. Safari Web Content uses >1,4 GB physical RAM.
Sure, I also have a lot of other Applications open, but normally Safari seems to be the one that regularly uses most of the RAM.
Virtual memory might be an issue - the System partition with OS X is 100 GB in size, after a reboot I have about 17 GB free drive space, at the moment there are 12.7 GB free drive space.
I admit, that I sometimes have several windows with maybe 10..20 Tabs open in Safari, but it is very difficult to avoid that for me.
- When the MacBook gets unresponsive, I'm often using the
purgecommand in terminal, which helps for a short while but not for a long time - Closing
Safariand starting fresh also helps (but is annoying) - Restarting the Mac also helps, but I do not want to do that each day - I usually do it every 5..12 days.

purgeplease grab two screen shots and upload them. 1. Showing the activity monitor CPU panel with processes sorted by CPU sorted with most CPU on top. 2. showing the bottom of the memory tab - active, wired, inactive, free and the pie chart. – bmike Mar 23 '14 at 13:18