Re: Advantage of 64bit Java vs 32bit ? Performance?

(source:http://www.oracle.com/technetwork/java/hotspotfaq-138619.html)
What are the performance characteristics of 64-bit versus 32-bit VMs?

Generally, the benefits of being able to address larger amounts of
memory come with a small performance loss in 64-bit VMs versus running
the same application on a 32-bit VM. This is due to the fact that ever=

native pointer in the system takes up 8 bytes instead of 4. The loadin=

of this extra data has an impact on memory usage which translates to
slightly slower execution depending on how many pointers get loaded
during the execution of your Java program. The good news is that with
AMD64 and EM64T platforms running in 64-bit mode, the Java VM gets some
additional registers which it can use to generate more efficient native
instruction sequences. These extra registers increase performance to
the point where there is often no performance loss at all when comparing
32 to 64-bit execution speed.
The performance difference comparing an application running on a 64-bit
platform versus a 32-bit platform on SPARC is on the order of 10-20%
degradation when you move to a 64-bit VM. On AMD64 and EM64T platforms
this difference ranges from 0-15% depending on the amount of pointer
accessing your application performs.