Fedora 9 32 or 64 Bit - Which One?

Kevin Kofler kevin.kofler at chello.at
Sat Oct 25 22:52:15 UTC 2008


Bill Davidsen <davidsen <at> tmr.com> writes:
> At the moment, unless you have really large application which benefit from
> 4G memory, the hassle of 64 bit is more than some benefit,

There's no hassle. It just works.

> and it appears that 32 bit application may be nicer to cache and therefore
> somewhat faster.

Where are your numbers?

On all the benchmarks I've seen, 64-bit clearly wins, and there are several 
explanations for that, in particular:
* x86_64 has more registers to use.
* SSE can be used by default on x86_64 because all x86_64 CPUs support it.

Please show your numbers or I'll have to dismiss your remark as nonsense.

> You can use more than 4G of memory in the kernel, to be used to run smaller
> applications, although Alan Cox indicates using a PAE kernel is slower. I
> haven't seen that, so I suspect it's one of those "in some cases" things.

PAE is obviously slower, for all apps (it slows down all the memory accesses), 
it's just a hack to keep 32-bit viable for a longer time, 64-bit is the real 
solution.

        Kevin Kofler




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