Is Page file useful?

I have a Dell Studio 17 with Win 7 and 3 GB ram... and as a norm have reserved space for page file upto 3 GB!

But my concern is that most it the time my RAM is being used only around 50% and they system starts using the page file! why is it not using the RAM to its full potential! and what can be done about it?

RAM is used for most frequent files.Most OS use page files to store data and load it into RAM whenever necessary.
You can change size of Page file, but it is recommended that you shouldn't keep it less than that of RAM.

* Go to control panel>system and security>system
* Click on advanced tab
* In the performance section click on settings
* Again click on Advanced > click on Change in the Virtual Memory section
* Change the virtual memory [pagefile size]
* restart your computer

More information
TweakHound - Tweaking Windows 7, Page 7
Learn Best Practices for Optimizing the Virtual Memory Configuration

My Ques why is it not using full RAM and what are adv n disadv of decreasing pagefile size... and how much i reduce it to?

Windows tries to keep RAM free for programs and other services.Also files brought in RAM, are sent back to pagefile in case they are needed back again.They are not kept in RAM.This is overly simplified but I hope that it gives a fair idea.

so is it safe if i reduce the pagefile size? how much can i reduce it to?

Don't reduce it beyond the size of your ram

lol... that i get but what will happen if i will!!! any idea?

Theoretically, lower paging should be great for performance if you have RAM big enough, and 3 GB looks better than 'enough'.

For devices, such as laptop - lower use of disk could reduce battery usage but it might end up in more heat being generated (by excessive use of RAM).

K

ankushkool said:
But my concern is that most it the time my RAM is being used only around 50% and they system starts using the page file!

it is because, the OS memory scheduler(Virtual Memory Manager (VMM) on Windows platforms.) kicks in, if it finds the RAM usage more than 50%, and swaps page to and fro HDD(secondary storage).

ankushkool said:
and what can be done about it?

In my experience, if you are not using optimal memory(not running resource intensive applications,GAMES,MMOs,GFX apps, etc) you could set the page file to zero.

Understanding the Impact of RAM on Overall System Performance

summary:
As physical RAM increases, the machine’s dependency on virtual memory decreases. The less a computer has to depend on virtual memory, the more efficiently that machine will run.

i am sure this topic has been beaten to death pretty much in every tech forums on the internet, just search and confuse yourself, good luck