What is... Virtual Memory
Understanding why you get those "Virtual Memory"
messages
Author: Paul Landers
RAM (Random Access
Memory or memory) comes in two forms - real
and virtual. "Real" RAM comes in the form of memory modules
(also referred to as memory cards, memory chips or memory
sticks). You can read a more detailed article about RAM
here. Virtual Memory is a
space reserved on your Hard Disk Drive to act as a memory
overflow It's far more technical than that, but we aren't
going to get into the technicalities here). When the
Operating System is first installed, it reserves a space on
the Hard Disk Drive called a "Page File". The space it
reserves is generally between 1.5 and 3 times the capacity
of installed RAM in the computer.
When programs and files are opened, they are copied from the
Hard Disk Drive and worked-upon in RAM. When they're "Saved"
they're copied back to the Hard Disk Drive. When they're
"Closed" they are removed from RAM. RAM provides the "desk
space" for them to be spread-out and actioned. These open
programs and files often get too large to reside in the
available RAM. When this happens, the Operating System and
hardware manage the overflow by placing parts of the programs
and/or files in Virtual Memory (the Page File reserved on the
Hard Disk Drive). Those parts are then "swapped" to and from
Virtual Memory as and when they are needed.
Information in RAM can be accessed far quicker
than information on a Hard Disk Drive. As such, each
time information is swapped to and from Virtual
Memory, the system slows down. The more that Virtual
Memory has to be accessed, the more the system slows down.
Additionally, and because it resides on the Hard Disk
Drive, the storage space allocated to Virtual Memory (the
Page File) becomed "Fragmented". You can read a more
detailed article about Hard Disk Drives here. This
fragmentation causes an even greater system-slowdown as
files and space get more difficult to access. Eventually,
the system generates a message warning you about its "Page
File" or "Virtual Memory" - the exact message will vary
depending on the circumstances.
So, now that we know what it's all about, what does one do
if and when a Virtual Memory message is displayed? Well, if you
only get the message on the rare occasion, here are some of the
things you can do:
- Close (not minimise) any open files
and/or programs that you are not currently using.
Minimising something simply removes it from view, not from
RAM.
- Defragment your Hard Disk Drive. This has the effect of
"cleaning" your Page File, making it easier and quicker to
access. You can read how to do that here.
- Increase the size of your Page File via the options in
the Control Panel. Only do this if you're confident
you know what you're doing.
If you get a "Virtual Memory" message regularly, it's likely
your computer is screaming out for more RAM. You should
consider upgrading the capacity of your RAM.
You can read a detailed article about maintaining and
servicing your computer here.
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