Symptom
The Process Viewer application incorrectly displays zero (0.00) or negative (-0.??) "% Memory" values for processes if 2.0 GB of memory is installed in the computer.
Solution
This is a cosmetic issue only. It does not indicate any actual issue with the installed RAM or other computer hardware.
Alternatively, you may use the top Terminal command to get information on memory usage of processes. For more information on using top, execute "man top" in the Terminal (/Applications/Utilities/).