Gentoo Archives: gentoo-user

From: Alan McKinnon <alan.mckinnon@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Status of Gentoo
Date: Fri, 14 Mar 2008 21:03:50
Message-Id: 200803142257.26094.alan.mckinnon@gmail.com
In Reply to: Re: [gentoo-user] Status of Gentoo by Mark Knecht
1 On Friday 14 March 2008, Mark Knecht wrote:
2 > It's an interesting question and one I've not tried to test. Does an
3 > AMD64 machine running a 32-bit or 64-bit install run faster or slower
4 > with one or the other.
5
6 Simple logic dictates that 32 and 64 apps will *generally* run at
7 exactly the same speed, mostly because the amd64 arch is x86 with 64
8 bit extensions. Unless your app is compiled to actually use the 64 bit
9 features (you'd be surprised just how few are), 32 and 64 bit code
10 tends to run at exactly the same speed using exactly the same opcodes
11 at exactly the same clock rate.
12
13 For any app not using intensive 64 bit arithmetic (super-duper math/sci
14 stuff and seriously intensive graphics are the only ones I can think of
15 off-hand) it's hard to see a benefit for amd64 with current desktop
16 memory loads.
17
18 The real benefit of amd64 becomes very obvious when you are dealing with
19 apps that consume huge amounts of memory and 3G of addressable space
20 for all apps just doesn't cut it. This is the problem amd64 was
21 primarily designed to solve. When you have an app that does benefit
22 from amd64 - like Sybase IQ just to pull a random selection from a
23 hat :-) the difference is astounding.
24
25 Conventional desktops? Never seen a benefit yet on a normal desktop.
26
27 --
28 Alan McKinnon
29 alan dot mckinnon at gmail dot com
30
31 --
32 gentoo-user@l.g.o mailing list