INTRODUCTION
Kernel memory resource bottlenecks can drastically limit Exchange 2003 scalability. Kernel resource usage may vary greatly from one Exchange server to another. A hardware...
Published Dec 07, 2005
Version 1.0
Blog Post
A couple of extra details on comments about /3GB on Windows Standard editions and having more than 4 GB of RAM in a server:
(1) In Windows 2000 Standard edition, the /3GB switch did not work correctly. I don't just mean it had no effect--it could have very bad effects. It worked kind of halfway and could blue screen you.
For Windows 2003, the /3GB switch works correctly for Standard, Enterprise and Datacenter versions. The Windows and Exchange teams need to get together and agree on the supportability statements, obviously. On the Exchange side, we've had no problems due to Standard with the /3GB switch, and a lot of people are doing it.
(2) The best practice if you have more than 4GB of physical RAM in an Exchange server is to actually, physically remove it from the box. You can also disable it with registry keys for the same effect. However, if you leave it enabled, it will, just by being there, eat up some more kernel resources that are better allocated to other uses.
(1) In Windows 2000 Standard edition, the /3GB switch did not work correctly. I don't just mean it had no effect--it could have very bad effects. It worked kind of halfway and could blue screen you.
For Windows 2003, the /3GB switch works correctly for Standard, Enterprise and Datacenter versions. The Windows and Exchange teams need to get together and agree on the supportability statements, obviously. On the Exchange side, we've had no problems due to Standard with the /3GB switch, and a lot of people are doing it.
(2) The best practice if you have more than 4GB of physical RAM in an Exchange server is to actually, physically remove it from the box. You can also disable it with registry keys for the same effect. However, if you leave it enabled, it will, just by being there, eat up some more kernel resources that are better allocated to other uses.