WinCache Object Cache provides a persistent memory-based backend for the WordPress object cache. WinCache must be available on your PHP install.
WinCache is a Windows-optimized extension for PHP which significantly improves performance of PHP applications by using byte code, file and object caches. More information about using WinCache can be found in PHP documentation: http://www.php.net/wincache.
WinCache extension for PHP can be downloaded from http://www.iis.net/download/WinCacheForPhp.
WP_APC_KEY_SALT to something that is unique for each install (like an md5 of the MySQL host, database, and table prefix).