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-   -   Would it be smarter to install the 32bit version or the 64bit version? (http://www.linuxquestions.org/questions/slackware-installation-40/would-it-be-smarter-to-install-the-32bit-version-or-the-64bit-version-4175497300/)

pcninja 03-06-2014 03:29 PM

Would it be smarter to install the 32bit version or the 64bit version?
 
I am currently using the 32bit version of Slackware 14.1, but I was wondering if (on my hardware) there would be any benefit to using the 64bit version instead.

My hardware:
Intel 495PSN
Intel "Prescott 2M" Pentium-IV 640 (3.2Ghz)
2GB of 533MHz? of RAM (dual channel, 2x 1GB sticks)

(I don't think my video card or what drives I use matter)

smallpond 03-06-2014 03:38 PM

I used to think that if you could run either, you should use 32-bit. Addresses are smaller, so more code should fit in cache, which means that 32-bit code ought to have fewer cache misses. So I tried running some CPU benchmarks in 32-bit mode vs. 64-bit mode. Turns out that CPUs spend a lot of time copying data, and they can move twice as many bytes per word in 64-bit mode, so realistic 64-bit benchmarks beat 32-bit benchmarks, despite having more cache misses. Now I always use 64-bit when available.

metaschima 03-06-2014 03:49 PM

It seems to support 64-bit:
http://ark.intel.com/products/27480/...=pentium+4+640

So, yes you should use the 64-bit version, unless you have a good reason not to. If you really need 32-bit apps you can use multilib to run it under 64-bit.

jamison20000e 03-06-2014 04:16 PM

Can run almost all 32-bit apps and\or environments on a 64-bit system 99.9% not the other way around.

jmccue 03-06-2014 04:53 PM

With 2 gig of ram, I would go with 32 bit and disable PAE if turned on. With that said, I doubt you would see a difference between the two.

genss 03-06-2014 07:03 PM

Quote:

Originally Posted by smallpond (Post 5130178)
I used to think that if you could run either, you should use 32-bit. Addresses are smaller, so more code should fit in cache, which means that 32-bit code ought to have fewer cache misses. So I tried running some CPU benchmarks in 32-bit mode vs. 64-bit mode. Turns out that CPUs spend a lot of time copying data, and they can move twice as many bytes per word in 64-bit mode, so realistic 64-bit benchmarks beat 32-bit benchmarks, despite having more cache misses. Now I always use 64-bit when available.

good you did effort :)

also 64bit instructions are longer (thanks to intel)
not that they have to be used

but 64bit you get twice as much registers and most of them are twice as long, so they can do more in most cases
like you got a loop that does something to some data.. like a picture
the picture probably won't fit in the cache anyway (like i got 2MB per core, my guess is about 75% is useful for a program)
so the code itself... i mean loop unrolling can get better performance despite having more code (depending on a case ofc)

PAE shouldn't influence much


@OP
amd64 all fine unless you run out memory, not that you will save some amazing amount by going 32bit only

ReaperX7 03-06-2014 09:50 PM

Let's make this easy:

If you have 64-bit capable hardware, you should use 64-bit software to get the maximum capabilities from your hardware. If you need 32-bit afterwards, use multilib.

Only use a 32-bit OS if you have 32-bit hardware.

jefro 03-06-2014 09:59 PM

I still say ram is the choice even if you have the ability to run full 64 bit.

At 2G you are at a crossroad. I'd still consider the 32 bit version to leave a bit more real ram. 64 bit helps you with using more ram and larger program access to ram. It wouldn't help you to try to run a 64 bit application needing 4 gig of ram.

In a normal home system, I doubt you'd notice much either choice.

jamison20000e 03-06-2014 10:21 PM

How long until 32-bit systems and\or software gets unsupported? I've only ever have had 4Gs RAM under my 64-bit so can't say but would look at using 32 as going backwards? They are free to try both and see or if you can up the RAM.

genss 03-07-2014 08:48 AM

Quote:

Originally Posted by jamison20000e (Post 5130344)
How long until 32-bit systems and\or software gets unsupported?

until we get a all around better cpu architecture then x86

PS on over 1Gig x86_64 should be better
it's not like you are going to run new, memory demanding, games on it (most everything else should run better)

pcninja 03-07-2014 03:54 PM

I guess I will stick with 32bit.

astrogeek 03-07-2014 04:12 PM

I tend to lag everyone else in hardware specs and was excited to get my first 64 bit machines a couple of years ago.

After initially installing 64 bit Slackware 14.0 I eventually reverted them to 32 bit 14.1, both are now running Slackware 14.1+ 32 bit (as are most of my other machines).

I see no notable performance differences (each has 2GB RAM, AMD processors).

My reasons for reverting were due to a single legacy app that requires Wine and a preference to not go multilib, another application that requires Qt3 among other things and the stack did not build well under 64, and the desire for commonality across my own systems which still includes a roomfull of 32 bit machines.

I have a new hard drive in transit for one of them and will likely set up a 64 bit install on a separate partition for fun, but I have no compelling need to run 64 bit... yet.

Conclusion: you'll probably do fine with 32 for now.

273 03-07-2014 04:23 PM

Quote:

Originally Posted by pcninja (Post 5130172)
(I don't think my video card or what drives I use matter)

The size of the drives may. If you want to run multilib you need more hard drive space.



Quote:

Originally Posted by genss (Post 5130262)
also 64bit instructions are longer (thanks to intel)

<COUGH>Erm, AMD surely? https://en.wikipedia.org/wiki/Amd64#History_of_AMD64 <COUGH>

genss 03-07-2014 04:43 PM

Quote:

Originally Posted by 273 (Post 5130790)

there a long time war is brewing

in short;
http://www.agner.org/optimize/blog/read.php?i=25

i don't blame intel, amd would probably do the same (i would:))
also designing cpus is a looong process, just wish they talked to each other

273 03-07-2014 04:51 PM

Quote:

Originally Posted by genss (Post 5130799)
there a long time war is brewing

in short;
http://www.agner.org/optimize/blog/read.php?i=25

i don't blame intel, amd would probably do the same (i would:))
also designing cpus is a looong process, just wish they talked to each other

I would like to blame Intel just because, and I'll admit that either could be thought of as being "to blame" but I was referring to this
Quote:

Originally Posted by page linked

In 2001, Intel launched their first 64-bit processor named Itanium with a new parallel instruction set. Instead of accepting the new Itanium instruction set, AMD developed their own 64-bit instruction set which - unlike the Itanium - was backwards compatible with the x86 instruction set. The market favored the backwards compatibility so AMD won this time and Intel had to support the AMD64, or x86-64, instruction set in their next processor.

AMD being the ones to develop the instruction set though I suppose they had their hands tied by the past.


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