I am running SQL Server 2008 R2 Standard (x64) on a Windows 2008 R2 Enterprise x64 Virtual Machine (vmware ESX 4.1).  I have given the VM 8GB of RAM and 4 vCPUs.  I am constantly getting the SQL Cache Memory alerts saying that my threshold has been surpassed.  I've done researc on the Internet but could not find how to resolve this.  Please Help explain what this indicates and how it could adversely affect my SQL Server performance.

Kevin