The WinCache Object Cache plugin provides a persistent memory-based backend for the WordPress object cache. An object cache is a place for WordPress and WordPress extensions to store the results of complex operations. On subsequent loads, this data can be fetched from the cache, which will be must faster than dynamically generating it on every page load.]
“WinCache is a Windows-optimized extension for PHP which significantly improves performance of PHP applications by using byte code, file and object caches.”
Note: if you use the old version that you have downloaded from blog post about how to Make WordPress faster on IIS with WinCache 1.1, then it is highly recommended to upgrade to the version from wordpress.org.
The plugin is based on the code written by Mark Jaquith for his APC Object Cache WordPress plugin. Thanks to Andrew Nacin for pointing me to that plugin and suggesting to publish similar one for WinCache.
You can download the plugin from WordPress Plugin Directory.