This should only be used when ram usage is unexplainably high. In some cases it can use 8gb and causing the server to hit 95% or more ram usage at all times. By default, exchange will eat up ram to make itself run smoother and give up ram as needed to other programs but it doesn’t always work that way.
This will require restart of the exchange info store service when done so it should be done after hours.
Start -> ADSIedit.msc, or navigate to Start -> All Programs -> Administrative Tools -> ADSI Edit.
Right click the root of the tree view on the left and select Connect To. . . On the Connection Settings screen select the Select a well known Naming Context option and from the drop down list choose the Configuration option. Then click OK.
Once connected to the Configuration Naming Context, navigate to the following item:
Configuration -> Services -> Microsoft Exchange -> ”Organization Name” -> Administrative Groups > ”Exchange Administrative Group” -> Servers -> ”Server Name” -> InformationStore
Edit the following lines and set them to these values:
Exchange 2010:
Min – 1GB: msExchESEParamCacheSizeMin = 32768
Max – 4GB: msExchESEParamCacheSizeMax = 131072
Exchange 2007:
Min – 1GB: msExchESEParamCacheSizeMin = 131072
Max – 4GB: msExchESEParamCacheSizeMax = 524288
When done, restart the exchange info store service and the ram usage should drop significantly.