I was helping a client who complained that Firefox on her Mac slow – spinning wait rainbow. Then another person called saying the same issue. This required some investigation.
Both computers had the newest version of Firefox installed. Both had the latest OS installed, and both had 4GB of ram. Figuring it was low on memory I first restarted the computer to see if it helped. It did not.
Running just Firefox I watched Activity Monitor to see if there was other activity running. There was not. So this was probably just junk that had accumulated or perhaps some plugins that were causing issues. I disabled all plugins and still slow. I deleted the cache and reset the browser, still slow.
So the laptop she is using is a MacBook Air about 4 years old. I looked at the amount of free memory. Out of a 250 GB drive, she only had 25GB free. Apple recommends 25% of the total drive space free, which in this case is about 63GB. I rounded up for those math majors. This was a major cause of her spinning. Her computer was very limited on the virtual memory which causes this kind of slowness.
It didn’t help that Firefox doesn’t run in parallel which is scheduled to be fixed with the next version due in the next few months at the most. So in macs that have low system resources using Safari/Chrome might be best until Firefox updates. However as I wrote before both Safari/Chrome are removing functionality like Flash, Java, Silverlight and so on and more, so they may not be compatible with the websites that you want to visit.
There is not a clear winner for the average mac user using a web browser. Most people who use macs, need to have a variety of browsers to be compatible with all business websites. Often the most problematic websites are from the government, or older application compatibility.
I like Firefox even with this limitation. Oh, what happened to that female mac Firefox user? Did she get her problem solved?
Yes, it turns out that due to the junk built up on her computer, it made more sense to reinstall from scratch and reinstall her applications. Once I did this, performance was fantastic. It makes sense to rebuild/refresh computers that are heavily used whenever issues like this occur.