#5965
RAMMap is a small, free but professional tool for analyzing and cleaning up physical memory usage, developed by Microsoft. It presents detailed RAM usage information in different ways, enabling you to understand the memory usage of your system and applications and how Windows manages the memory allocation. In addition, it can effectively clean up memory.

#2736
Process Monitor is an advanced Windows OS and application monitoring tool (equivalent of Filemon + Regmon), specially designed for system troubleshooting and malware hunting for experienced users. It's released in the excellent Windows Sysinternals, and offered by Microsoft TechNet, so its accuracy and reliability are needless to say.

#1675
Sysinternals Suite (AKA: Windows Sysinternals Suite) is a tool set originally developed by Winternals company for internal use, aimed at resolving all sorts of problems that engineers might encounter in their usual work. Later it was placed on the Internet for free downloads, and some tools also opened source. Till today, Sysinternals has long been popular with high praise in the IT industry.

#217
Process Explorer is one of the famous Sysinternals' products - enhanced Task Manager, its biggest characteristic is killing any process at once, even including the key system processes, this is too far behind to catch up for the Task Manager.