Here are some symptoms which indicate your computer could benefit from a memory upgrade:
Applications run slowly or become unresponsive
If your applications take a long time to startup or become unresponsive for a few seconds, chances are your system is running low on free system memory.
Parts of the display on your screen appear to be missing
Sometimes insufficient free system memory can cause images or web pages to only partially load, or not load at all. Adding more memory provides the additional resources to allow your system to quickly load all types of media.
Video playback is choppy
Videos played from local sources and also from youtube require free system memory so that they can be buffered and played without pausing or stuttering. Insufficient RAM can result in choppy or frequently paused video playback.
Slow Boot-up
When there is insufficient installed RAM, this can result in your PC or Mac taking a long time to boot up. Upgrading your memory can often improve boot speeds by around 50%.
Low Memory messages appear
Sometimes your operating system will popup an explicit message that the system has run out of, or is very low on free memory, like this one from a Windows system:
You may also see a similar message generated by a particular application when it is using a lot of RAM.
Messages that include the text 'Insufficient Memory', 'Out of Memory', or 'Insufficient System Resources' are signs that you need a memory upgrade.
System utilities show low free system memory
Both Windows and Mac systems have a built-in utility to help you see how much free system memory you have.
The below video shows how to check free system memory on a Mac:
For a guide on how to check free system memory on a Windows PC, watch the video below: