Microsoft Knowledge Base Article 914036 contains the following introduction:
The limit for the multi-values object in a non-linked attribute in the Active Directory directory service is defined by the operating system version and its forest functional level. Microsoft Windows Server 2003 increases the maximum numeric value that can be stored in a non-linked attribute.
The following table contains estimations of the maximum value that can be stored in a non-linked attribute in Microsoft Windows 2000 Server and in Microsoft Windows Server 2003.
|Operating system version||Forest functional level||Value|
|Windows 2000 Server||Mixed mode or native mode||800|
|Windows Server 2003||Windows 2000 Server (default)||800|
|Windows Server 2003||Windows Server 2003 interim||1300|
|Windows Server 2003||Windows Server 2003||1300|
Note The actual value of a non-linked attribute varies depending on the length of characters and on the length of character sets in Active Directory.