In Exchange 2007 SP1 the default database cache size is set to 128MB, to allow for better cache growth. The new guidance is to increase the DatabaseMaxCacheSize from 128MB to 512MB (on Hub Transport servers with more than 4GB of RAM)

This can be done editing the EdgeTransport.exe.config file as shown below:-


More details can found on Microsoft Exchange Team Blog

Written by Daniel Kenyon-Smith