There is NO physical limit in Windows NT 4.0.

As you add users, groups, and computers to a domain, the size of the SAM (Security Accounts Manager) database increases, affecting performance. If you have a computer which acts as a domain controller (with no other major NT services running, such as File & Print, RAS, DHCP, WINS, DNS, SQL, SNA, and Exchange), you can use the following table as a guideline:


Number    SAM   Registry         PagedPool      CPU          Paging    RAM
of users  size  size             size           needed       file size

10,000     15      25 (default)   50 (default)  P or A         128      64
15,000     20      30             75            P or A         128      64
20,000     30      50            100            P or A         256     128
30,000     45      75            128            P or A         332     166
40,000     60     102            128            SMP            394     197
50,000     75     102            128            SMP            512     256
60,000     80     102            128            SMP            1Gb     512
As the size of the domain increases, monitor:

* System Boot time, which increases as the system pages in the entire account database.

* Time to create a group, which increases as the total SAM size grows very large.

* Time to add users to a large group, which increases as the SAM grows above 60 MB.

* Bandwidth required to replicate a large SAM.

NOTE: P=Pentium, A=ALPHA, SMP=Multi-Processor.

NOTE: Add RAM to improve performance.

NOTE: Processor speed only becomes important as you add other services and functions.

NOTE: Add RAM as you add services and functions.

NOTE: Add RAM as you add services and functions.

NOTE: Add RAM as you add services and functions.

NOTE: Add RAM as you add services and functions.

NOTE: Add RAM as you add services and functions.

NOTE: Add RAM as you add services and functions.