Browser resource usage

The other day I had Safari running all day and before going to bed I started Activity Monitor and checked what's going on. I was surprised to see my Mac was swapping. It usually isn't, not any more after I got a new Mac mini with 4 gigabytes of RAM.

The cause for swapping was Safari 5 taking up just under 1 GB. Eh!??!

I did a test. I opened Safari, Firefox and Opera and loaded each with 3 tabs: Twitter, Facebook and Gmail and let it simmer for 5 hours.

Browser	Version	Initial RAM use	RAM use after 5h	CPU usage
Safari	5.0	185 MB	301 MB	0.1%
Firefox	3.6.3	160 MB	157 MB	3.3%
Opera	10.53	205 MB	249 MB	7%

I don't think I can afford to run Safari now that it uses so much memory. Incredibly, Firefox used less memory after 5 hours than right after loading the pages! I think if anyone these days says Firefox is a bloated browser, they are badly mistaken.

I also followed the CPU usage of the browsers. It seemed to stay constant, so I did not include initial and after-5-hours figure in the table. To Safari's credit, it runs fast and causes practically no CPU load even with these Javascript-intensive pages. Opera uses so much CPU, it would start to be noticeable if all the 3 users on this Mac would use Opera.

Based on the figures above, Firefox is my new default browser.