JBoss products are 100% pure Java, and will run on 32 or 64 bit hardware with a compliant JVM.

Benefits of 64-bit JVM on 64-bit OS & Hardware:

• Wider datapath : the pipe between RAM & CPU is doubled, improves performance of memory-bound applications

• 64-bit memory addressing gives virtually unlimited (1 exabyte) heap allocation (note, large heaps affect garbage collection)

Issues with 32-bit JVM on 64-bit OS & Hardware:

• On Linux x86_64, the JDK1.3 requires a work around to run.  See Linux64andJDK1.3

Conclusion:

Applications which run with more than 1.5GB of RAM (including free space for garbage collection optimization) should utilize the 64-bit JVM.  Generally speaking, applications which run on 32-bit virtual machines which do not require more than minimal heap sizes will gain nothing from a 64-bit JVM and will likely require more memory to run the same code (the 64 bit addresses among other issues).  Barring memory issues, 64-bit hardware with the same relative clock speed and architecture will not likely run Java applications faster than their 32-bit cousin.  Because many server applications require a great deal of memory, 64-bit hardware should be considered for new purchases.

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