Firefox is one of the most used web browsers,
but many of you will have realised the amount of RAM it hogs.
When many tabs are open it can quite easily exceed 200MB of RAM. There's a simple trick to free memory when you need it.
Unfortunately, it isn't a permanent fix but it works. What happens is that when you minimize Firefox it uses much less memory. So, when you want to use your system running smoothly again just minimize Firefox until you need it.

1) Type about:config in the address bar and hit Go

2) Right click in the values space and select New >> Boolean

3) Type in config.trim_on_minimize and select OK

4) Change the value to True

5) Restart Firefox

Remember this only fixes it when minimized but can make a large difference.

that useful tutorial..
thanks for sharing

nice one, very helpful.