PerfMon 5.0 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The following versions: 6.0 and 5.0 are the most frequently downloaded ones by the program users. We recommend checking the downloaded files with any free antivirus. The actual developer of the free program is Microsoft. The program lies within System Utilities, more precisely Gadgets Widgets.
From the developer:
PerfMon allows you to open a Windows XP Performance console configured with settings files from Windows NT 4.0 version of Performance Monitor.
It demonstrates how to monitor local or remote system performance. It shows how to dynamically create timers, context menus, and graphic displays.
You may want to check out more software, such as Performance Monitor or WCAT, which might be similar to PerfMon.