Sun Performance and Tuning: Java™ and the Internet, Second Edition

When Does “64 Bits” Mean More Performance?

There has recently been a lot of talk about 64-bit systems. There are also claims that 64-bits are faster than 32-bits, and some of the fastest CPUs have 64-bit capability. Can you take advantage of 64-bit operations to make applications run faster? There have been several occasions over the last few years where systems have been marketed as “64 bit,” so what is the difference this time?

There is a lot of confusion surrounding this issue. Part of the problem is that it is not always clear what the term “64 bit” is referring to. I’ll start with a generic statement of the difference between 32-bit and 64-bit operations. We can then look at the many ways in which “64 bitness” has been applied over the ...