java version "1.3.1"
jdkgcj 0.2.3 (http://www.arklinux.org/projects/jdkgcj)
gcj (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
and the latest Sun Java in terms of performance... Would the newer degrade performance somewhat?
Specifically for memory there should be no change. You get to tell a JVM how much memory to use. Tell it to use 265MB and that is the maximum it will take (well, sorta - it actually takes a bit more than that but it is bounded). That is true in both the 1.3 series and the 1.4 series. There should be no noticible change one way or another with this.
It should not increase server load. If I guess that you are using Linux you will likely see an improvement over 1.3. In general the 1.4 release was focused on bringing new API's to Java and also improving the performance specifically on Linux. Solaris and Windows got a boost in performance too.
The current production Sun release is 1.4.2_03. I have been using it in production systems with no issues.