There are versions of server 2003 that can use more than 4GB of memory. msdn.microsoft.com/.../aa366778%28v=vs.85%29.aspx If you are using all the memory you have installed now, and you are running a version of 2003 that supports more than 4GB of memory, I would say install more memory. If the version you have installed does not support more than 4GB of memory, then there is no need to install more memory, as it will not be able to properly utilize it. support.microsoft.com/.../283037
We have a Poweredge T110 with Windows 2003 Server 32 bit, SP2.  The system has 4GB of RAM (2x2GB).  However, with what we do with the system, we are pushing the limits of RAM (mostly because of multiple remote desktop client connections).  Because the nature of the front-end systems that we use, we are stuck with Windows 2003 32 bit and cannot migrate to a 64 bit solution.  Does it make any sense to stick in an additional 2GB stick, or use 4 x 2GB sticks for 8GB and use the /3GB and /PAE extensions in boot.ini to try to take advantage of additional memory on top of a 32 bit subsystem?  Lastly, what is the upper limit of using >4GB on a 32 bit system?  I heard that Windows has a hard time being stable simply because the 32 bit OS cannot map much memory past 6 or 8GB.  What is my best course of action at this point?  And if I were to upgrade to say 6GB, is the system then running in dual channel mode still or is it back to single?  If I go to 8, should I do 2 sticks of 4GB or 4 sticks of 2GB?
Should I Add an Additional 2GB of RAM?