This wiki is a community-maintained resource about everything there is to know about IPFire.
The Memory page on the Status menu displays information about the use of physical RAM and the swap partition of your IPFire installation as well as a summary of the current conditions.
The memory graph shows the relative usage of the physical RAM. It distinguishes between the types of usage:
Please note that the standard view shows a timespan of one day. You can also bring up graphs for an hourly, weekly, monthly and yearly timespan if you click the appropriate links above the graphs.
The swap graph shows the usage of the swap partition in a similar manner.
The summary again shows the current usage of the physical as well as swap memory in a similar distinction as the graph above. However, in addition to showing the relative usage it also shows absolute values.