Enquiry,,,

Evan Klitzke eklitzke.lists at gmail.com
Sat Feb 3 01:44:27 UTC 2007


On Fri, 2007-02-02 at 14:57 -0500, Dmitriy Kropivnitskiy wrote:
> James Wilkinson wrote:
> > It's usually a bit faster.
> Just to avoid the confusion, are you saying that 64-bit capable
> processors are faster than 32-bit only or that application compiled for
> 64-bit architecture is faster then the same application compiled under
> 32-bit architecture on the same hardware. The reply to your post tells
> me that people think you mean the former, where I was talking about the
> latter. I will not dispute the claim that 64-bit CPUs are faster then
> 32-bit, cause I don't think they make 32-bit only CPUs anymore (at least
> in the x86 architecture). So any 32-bit CPU will be just plain outdated
> and therefore slower then any modern 64-bit (and 32-bit capable) CPU. As
> for the applications, I believe the difference should be negligible
> unless the application is trying to use a lot of RAM. I think I have
> seen some benchmarks confirming this, but at the moment I cannot seem to
> find them.

IIRC 64-bit architectures have more registers. This should make code
compiled for a 64-bit processor a little bit faster than code compiled
for a 32-bit processor, even if the application doesn't actually make
use of quantities larger than 32 bits. I'm not sure how much a
difference this actually makes in real world benchmarks, but it's
something to think about.

-- Evan Klitzke




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