WinCache is a PHP extension, similar to other opcode caching extensions, that provides several caching features for Windows environments. It is a great option for Moodle when hosted on a Windows Server with IIS. Since this extension allows for user caching in shared memory (RAM), it is also a great fit for Moodle Universal Caching (MUC). This plugin enables the WinCache store option in MUC, which can replace the default (and slower) File cache store.
Also consider using the WinCache info plugin to monitor WinCache usage.