Mac OS X System Monitor and Process Explorer Tool

atMonitor is an advanced monitoring tool for Mac OS X that displays system activity in real-time. It is designed to allow quick assessment of computer's state and it is powerful enough to make it a core utility in anyone's system troubleshooting toolkit.

atMonitor offers a better alternative to Apple's own "Activity Monitor" and combines the best of the features of many other existing monitoring utilities. It also adds an extensive list of unique features of its own. In addition to the standard CPU, Disk and Network info, atMonitor allows interaction with processes, setting up triggers, logging, purging RAM and much more. atMonitor can be displayed in the menu bar, as a stand alone floating window or in the dock icon.

The last version of atMonitor to support GPU related features is atMonitor 2.7.1.

The last version of atMonitor to support PPC is atMonitor 2.1.5, which is no longer supported, but available for those with PPC based Macs.


check MiniTop - Displays top 3 most CPU hungry applications.
check CPU - Supports multiple cores. Displays detailed process information and the top 3 CPU intensive processes.
check RAM - Shows memory specifications and the usage broken down into wired, used and free. It also tracks the top 3 memory hog processes and allows to "Purge" - recover memory (dev tools must be installed for the Purge feature to work).
check Temperature - Both CPU and GPU temperatures are reported.
check Disk - Displays the read and write performance of the most active disk. All mounted local and network disks are displayed and can be accessed with one click.
check Network - Displays the read and write performance of the active network interface. Shows the public, private and router IPs as well as the corresponding MAC addresses. Selecting any value will conveniently copy it to the clipboard.

Top Window

Top Window is the core functionality of atMonitor. It serves multiple purposes and is used for both monitoring and interacting with the system. For each process Top Window displays its PID and path, parent PID and path, description, arguments, environment, libraries and open files.


Triggers can be setup to activate any script when a predefined value reaches its target. For example, a script could be written to email system administrator when the CPU usage goes above 90%. Two sample scripts, one basic and the other one a little bit more advanced using GROWL, are included.


Utilities, accessible from "System Info", are a set of useful and domain specific system commands that can show detailed information about the system such as Kernel State, I/O Registers, Smc Sensors and more.


atMonitor allows to log all monitored values. The logs are saved in XML format with names in ISO 8601 standard and can be used to log and troubleshoot system performance.