This is a quick way to have easy visual access to your memory usage without having to rely on a Dashboard Widget, or even have Dashboard running for that matter. And you don't have to download anything. This comes standard with every new Mac running OS X.
Being involved with web design, and design in general, I find myself needing to monitor my memory usage on a daily basis. (mostly because of heavy Adobe Apps) If you are like me, you want to know how much of your precious memory you have left, so as not to launch that one extra application that crashes your machine and causes you to lose unsaved work. Mac OS X ships standard with an application called “Activity Monitor,” Located in your Applications > Utilities folder. By keeping this application in your dock, you can simply Control + click on it's dock icon and display a number of different charts to visualize the data, without keeping the application window itself open!
The Activity Monitor Dock Icon can display any of the following options, but only 1 at a time.
CPU Usage, CPU History, Network Usage, Disk Activity, or Memory Usage.
1. First, navigate to your Applications > Utilities folder, find the Activity Monitor application, and drag it's icon onto your dock and release. This is what the Activity Monitor Icon looks like:
2. Control Click (right click) on the Activity Monitor Dock Icon and select the Data Set you would like it to display, “Memory Usage” in my case. Note: Not all of the options display a pie chart. If you choose CPU Usage, it shows a bar that animates in real time similar to a band equalizer on stereo equipment.
3. You should then see the icon display a chart
4. The Colors: These categories change depending on which set of data being displayed, but here is what the colors stand for, as far as Memory Usage goes.