64-bit Kernel Question

[Adam Williamson]

On Mon, 2009-03-09 at 12:41 -0600, Petrus de Calguarium wrote:

> As memory requirements for 64-bit are anywhere from 50-100% greater and 
> the only appreciable difference is a "psychological" performance boost, what 
> REAL benefit is there, actually?

It's not psychological, it's just not noticeable in most regular
operations. Actually, most people wouldn't notice if you replaced their
CPU with one which was twice as fast (or, as the BOFH knows, half as
fast...), most of the time, because very few of the operations most
people do day-to-day are remotely CPU-bound. A few years ago I was
running a 2.4GHz (Pentium 4-era) Celeron as my desktop. The CPU fan gave
out, so the CPU throttled itself down to 800MHz and kept running. I
didn't notice for a fortnight.

The most common CPU-bound operation in our world, I guess, is
compilation, and you would notice a definite improvement in speed there,
running x86-64 vs x86-32 - not huge, but noticeable. Certain database
and I think scientific operations that are CPU-bound also derive a
significant benefit. It depends on whether the code can take advantage
of much bigger registers, AIUI.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Fedora Talk: adamwill AT fedoraproject DOT org
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