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Process Hacker is a feature-packed tool for manipulating processes and services on your computer. A free and open source process viewer with powerful process termination and memory searching/editing capabilities.

System Explorer is an enhanced Taskmanager that provides detailed information about running processes, startup programs, IE add-ons (BHOs), drivers, services network connections, system resources and more. It also keeps track of a history of processes that were started, and allows you to create file and registry snapshots that can be compared to analyze system changes in detail. System Explorer integrates online lookups into the right click menu for any process, driver or service, allowing you to retrieve additional information (and virus checking) from online sources including Google. »

Windows Task Manager is a task manager application included with Microsoft Windows NT family of operating systems that provides detailed information about computer performance and running applications, processes and CPU usage, commit charge and memory information, network activity and statistics, logged-in users, and system services. The Task Manager can also be used to set process priorities, processor affinity, forcibly terminate processes, and shut down, restart, hibernate or log off from Windows. »

Glances is a CLI curses based monitoring tool for GNU/Linux and BSD OS. Glances uses the PsUtil library to get information from your system. It is developed in Python.

Process Lasso is NOT yet another task manager. It is a process priority optimization and system automation utility. Priority optimization, affinity optimization, core optimization, automated rules, automated power schemes, you name it and Process Lasso has it. Although most consider Lasso the ultimate process priority optimizer, it does so much more!

WinSpy++ is a handy programmer's utility which can be used to select and view the properties of any window in the system. WinSpy is based around the Microsoft Spy++ utility that ships with Microsoft Visual Studio.

Mac OS X System Monitor and Process Explorer ToolatMonitor is the most advanced monitoring tool for Mac OS X that displays system activity in real-time. It is designed to allow quick assessment of computers state and it is powerful enough to make it a core utility in anyones system troubleshooting toolkit.atMonitor offers a better alternative to Apples 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, GPU, VRAM, FPS, 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. »

System Monitor is a tool to manage running processes and monitor system resources.

KSysGuard, also known as KDE System Guard and KDE System Monitor, is designed to make simple process control available to a user without needing to do any special setup - the defaults are usually perfectly adequate.

This tool controls programs, disk, CPU. Replace task manager, tweak and tune up XP or Vista. Speed up windows startup. Get rid of spyware and viruses.

Easy to use application for monitoring and controlling running processes.

Resource Monitor is a system application in Microsoft Windows operating systems. It is used to view information about the use of hardware (CPU, memory, disk, and network) and software (file handles and modules) resources in real time. Resource Monitor is available in Windows Vista and onwards only (In Windows Vista, it is known as Reliability and Performance Monitor). Resource Monitor can be launched by executing resmon.exe (perfmon.exe in Windows Vista). It was also on Windows 95, 95 OSR, 95 OSR2, 98, 98SE, ME, and NT. »