Of the tunings that can be applied to a Portal Server deployment, the JVM software tunings of the web container are the most important. It is important to use the tuning scripts to apply that configuration and to understand the changes made by those scripts. To be able to run those scripts it is necessary to edit a configuration file.
The tunable parameters in this file are crucial for Portal Server performance. Review those parameters carefully, especially those that determine the amount of memory that will be given to the web container.
With significant improvement in the JVM software scalability, the Portal application is also able to take advantage of the new JVM software parameters resulting in increased performance. An optimal configuration of the web container calls for a 2 GB of Java heap. As far as binding to Portal Server instances to CPUs, we now have great scalability up to 4 CPUs on a single instance and to even more CPUs with multiple instances of Portal Server.
Each version of portal is certified for JVM software tunings with the JVM software version that ships with the product. Using a non-certified JVM software is neither supported nor recommended. When deploying Portal Server in a production environment where all the component products are also deployed on the same server, it is recommended to use a machine with at least 4 GB or RAM.
It is being assumed that the system is being exclusively used for Portal server. If Access Manager and Directory Server resources are being consumed by other applications, then you might need to consider the tunings appropriately.