During interviews one of the questions I ask is: "What is the basic difference between 32-bit and 64-bit application?". The obvious one is the available address space for an application. The other one is performance - more details here.
btw: it is really scary how few sys admins know the answer to the question, even if just the address space part...
When the Opterons initially came out, and I could finally get my hands one, I was pleasantly surprised to see a 20% speed improvement going from -m32 to -m64 on the same computer.
ReplyDeleteIMHO there are situations in which IA 64-bit would have worse performance than 32-bit (many ctx switches and larger set of registers).
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