64 bit F7

[Chris Jones]

>> As they say: "Where is the killer app for 64-bit computing?"
> 
> Depends on who the "user" is, and what a "killer app" is to that user.
> 
> Most things that consumers need don't approach requiring (or seriously
> benefitting from) 64 bits. But some servers and workstations can get a
> lot from the wider data path and bigger address space.

Basically, code built in 64 bit mode is normally faster than the same 
code built in 32 bit mode. I say is normally, as it does depend on the 
code. Also, if you search the web for this you will find lots of 
interesting discussions about whether it is really the 64 bits versus 32 
that make the difference, or the fact that 64 bit gcc uses SSE/SSE2 by 
default whereas 32 bit gcc builds do not.

Bottom line for me is I have a scientific number crunching application - 
Compiling and running the same code, on the same machine in 32 or 64 bit 
mode, I find the 64 bit build is about 40% faster (about 20% if I enable 
SSE/SSE2 in 32 bit mode). This is very significant and for me makes 64 
bit builds well worth it.

Chris