Be sure to use -XX:LargePageSizeInBytes=2m This flag should improve performance of Java server applications 2-5%. Of course you mileage will vary. It may help client applications as well. When running 32-bit Sun J2SE 5.0_04 or earlier on Solaris x86 / Opteron systems. The largest page size that AMD Opteron supports is 2mb. These versions of the JVM assume a 4mb large page size, as it is on Intel Xeon processors. J2SE 5.0_05 and later will fix this, as do the latest Java SE 6 (Mustang) binaries on java.net. http://www.java.net/download/jdk6/binaries/ Here's a sample command line for Java server applications on Solaris 10 x86 32-bit with 5.0_04 or earlier. If server class machine with J2SE 5.0 (2 or more cores, 2 or more GBs of RAM) java -Xms3g -Xmx3g -XX:LargePageSizeInBytes=2mb _JavaApp_ If you're running J2SE 1.4.2: java -server -Xms3g -Xmx3g -XX:UseParallelGC -XX:LargePageSizeInBytes=2m _JavaApp_ (you should download and test J2SE 5.0, you'll probably be pleasantly surprised)