Pagefile is used to make up for the amount of RAM your computer doesn't have to keep doing the things your demanding it perform when it doesn't have the hardware. WAY back in the day, it was common for Windows to say "Out of Memory" and then lock up, so they created the 'pagefile' out of the Hard Drive space to 'make up the difference' when Windows needs more memory to do things. if your a common 'multitasker' 2-4GB isn't enough usually need at least 8, with many people now sitting at 16GB (like myself) because you do NOT open only one Webpage, then close that open ONE email, close that, open ONE word document, then close that. You usually have ALOT of webtabs open, with multiple emails, several documents, Instant Messaging (skype), streaming music, etc. all at the same time, that means alot more RAM is needed for your computer.