One frequent question we encounter with regard to performance and speed is “how much RAM do I need?” While increased RAM will help significantly in some cases, RAM is not always the bottleneck contributing to the performance deficit you are working through. How do you then determine if more RAM will help you and your computer? The Activity Monitor application has several wonderful tabs built in. These tabs include Mass Storage Usage, Network Throughput and Memory Allocation.
In Activity Monitor, select the Memory tab toward the bottom of the application window. Listed in a few columns with a corresponding pie chart will be the RAM usage of your Mac, broken into several different categories. To begin with, in the lefthand column, there are five main listings: Free, Wired Active, Inactive and Used. “Free” is the amount of addressable RAM in your computer not currently allocated to any process. The second item, “Wired,” is the amount of RAM that cannot be moved to mass storage because it’s being used by the system.
Next in the list is Active RAM; Active is the data in the RAM recently used. Inactive RAM is RAM that contains information from applications or processes that have been ended. This RAM is available to the System, but if the application which parented this wired RAM should be reopened, it would become Active again and its information would not need to be reloaded from mass storage. Used is the sum of the four previous categories of RAM in the machine; Used plus Free should equal the total RAM installed in the computer.
The second column contains how much data from RAM has been written elsewhere—or Virtual Memory. In this column, the one statistic that will alert you to the need for more RAM is Page outs. Page outs are the total number of times the System has written contents of RAM to mass storage because there was inadequate RAM in the system.