Benefit of 64-bit Java

[Peter Callies]

I know running the VM in 64-bit mode allows for large heap sizes. Aside from this, is there any benefit to using 64-bit mode?

[Steven E. Protter]

It allows java to tie up memory faster by grabbing it in bigger chunks!!!

That joke aside, I suppose for large memory block operations, they will run faster.

Also, more memory can be addressed.

SEP

[Paddy_1]

(a)Extended Heap Space
(b) Arrays may be indexed by "long" values. That means arrays are NOT implicitly limited to no more than the highest 32-bit int value,namely, 2,147,483,647
(c)It also means that the JVM on that platform does not incur the emulation penalty of a 32-bit application on 64-bit hardware

[Peter Callies]

I ran the SPEC JBB2000 benchmark in both 32 and 64-bit mode. 64-bit was about 1% faster which might have been purely coincidental as I didn't have complete ownership of the server while the benchmark was running. So I'm not sure if 64-bit really is faster. I'm going to try the benchmark again.