rlcastro07

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I have a laptop with AMD athlon X2 QL-60 processor. I've read online that it can support 64bit OS. Is this true? Please confirm.

And now i am planning to install a 64bit OS. Will it get better? any advantages over 32bit?

Thanks very much!

{BBI}Nexus{BBI}

That's correct it does support a 64bit OS. However, there's no point in doing that if you're using less than 4Gb of ram.

AlucardZero

There's no point if you don't run applications that will make use of the additional SSE registers (like mathy applications). 64-bit programs will use more RAM.

johnsfine

I think all that Athlon X2 models support 64bit.

It depends on what programs you run and may depend on how much ram or disk space you have.

You probably won't find any solid comparisons and will end up guessing. The performance difference probably will be small anyway.

You will probably get lots of contradictory and/or misleading advice, such as the first reply that implies the decision should be significantly influenced by whether you have more or less than 4GB. I think that is the range where memory size has the least impact on the 32bit vs 64 bit choice.

If you had 0.5 GB of ram and/or less than 80GB of hard disk, you might be seriously concerned about the fact that a 64 bit Linux distribution typically needs a little more disk space to install and a little more ram to run. So choosing 32 bit would be wiser.

If you had 8GB or more of ram, you might be concerned that the 1GB kernel virtual limit in 32 bit Linux may constrain the use of physical ram. So choosing 64 bit would be wiser.

In the 2GB to 6GB range of ram, I don't think ram size is an important input to a rational choice between 32 bit and 64 bit. Unfortunately, I don't have a better rational input, so you are left with a guess.

Some people may want to run individual processes so big that they need 64 bit regardless of the more typical performance considerations in the 32 bit / 64 bit decision. For such processes it is probably not reasonable to have just 4GB of physical ram, so if you have 4GB or less of ram experts here would assume you aren't running processes that fundamentally need 64 bit. Bit even if you had 12GB of ram, I still would guess you aren't running any process that fundamentally needs 64 bit.

ronlau9

Without knowing what kind of applications you're going to use it is difficult to say if you need the 64 bits performance .
To be honest I am use them both.
In a normal home situation it make no difference beside the fact that booting up and shutting down is quicker using 64 Bits

btncix

If you are planning to go with Slackware64, first check to see that the software packages you want to install and run are available for 64 bits. Like the quote above says, you can set up multilib to handle 32 bit binaries, but I don't know how easy/difficult that is.

Also, while 64bit allows for more memory capacity, it's more involved than that. Others hopefully can explain this too you better and in more detail, but I think 64 bit systems can be faster than 32 bit systems because of their ability to execute more instructions per cpu cycle. Personally, I can't tell much of a speed difference, but I haven't objectively measured this nor do I do things that are that cpu intensive.

If you have the hard drive space, create separate partitions and install both the 32 and 64 bit systems so that you can play around with both. If you go ahead with slackware64, let me know how the experience turns out.

johnsfine

No. They don't have the ability to execute more instructions per cycle.

64 bit mode has a slightly higher average instruction size, and either directly or through alignment issues or through cache issues, a slightly higher instruction size can lead to fewer instructions executed per second.

The big advantages of 64 bit mode are it has twice as many registers, plus the compiler will generate code for SSE rather than legacy floating point by default. Either of those can cause the same program to be compiled into fewer instructions. The reduction in number of instruction may be slightly more than the reduction in average instructions per cycle, resulting in faster execution.

A big disadvantage of 64 bit mode is that pointers are twice as large, so programs using a lot of pointers must move around twice as much data, which results in more cache misses and slower execution.

It is very hard to predict whether a given program would be faster or slower after balancing all those factors. Very few people have done and published careful enough controlled tests to tell whether programs are faster or slower.

Almost all the controlled tests I've done myself have been with software that has a lot of L2 cache misses (hurting 64 bit mode more than 32 bit mode) that was compiled with a compiler that is much better than gcc at dealing with the register shortage of 32 bit. So my results of 32 bit being significantly faster are probably very far from typical.

btncix

Appreciate the clarification johnsfine. Thanks.

I don't know the underlying mechanism for why a higher instruction size can lead to fewer instructions executed per second, but that's for another thread, time, or place.

OralDeckard

I used to install only 64 bit on my Athlon X2s. Then I found out that the speed difference is so ambiguous that choosing 64 bit for speed when I didn't have a known reason for it didn't outweigh the hassles. During installation the installer installed both 64 and 32 bit for most applications. Later, sometimes when I forced a 64 bit only installation, I had to go back and install some part of it with 32 bit as well.

So I figured, OK, the 64 bit hardware is here. These 64 bit processors execute 32 bit code faster than 32 bit processors, and later the 64 but software will catch up to the point that we don't have to include 32 bit versions as well.

If you don't already know if a reason to install a 64 bit OS, I think you would be better off to install a 32 bit. Although speed tests aren't definitive, for general use on a 64 bit processor, 32 bit seems to have a slight speed edge, which may simply be due to having fewer bytes to load and move around. I switch to 32 bit about a year ago, and am glad I did. I suspect I'll switch back in a couple of years. But reinstalling Linux is such a snap anyway, that's no problem.

marozsas

For desktop applications stay away for 64-bits OS !

I am using Fedora 64 bits in my desktop and I can't stand it anymore!

I can't use Internet banking because for it, the java based applications does not have support for 64 bits.
I can't use Google gears because it (and several others firefox plugins) area available only for 32 bits.
I can't use Picasa, Google Earth and any other wine based application because they exist only for 32 bits. In this case, I can install wine 32 bits, but I need to install A LOT of 32 bits libraries.
Some programs exist in repositories pre-compiled only for 32 bits. Of course I can download the source and compile then to 64 bits, but I need to install the Developing and Libraries packages.

So, for desktop applications on your personal laptop, stay with 32 bits.

rlcastro07

Hey guys thanks for all the suggestions you've given!

I appreciate it. THANKS!!!

I'll study this more.

jhwilliams

God yes, you should. The 32/64-bit debate happened largely in 2004. I think Windows folks might still be having this debate, I'm not really sure, who cares! But yea, everyone I know who uses linux runs 64-bit. And you should too.

There are still a few stupid things that don't work Out Of the Box like Adobe's various prorpietary bitfilth buckets, but O well. Actually, I think there's a beta that I'm using that works okay. In short -- everything works.

:-)


using = have, even. What a bummer to buy a new system and then have it tell you you don't have what you paid for. There are various "soft" reasons for going 64-bit: everyone else is, it's just whats happeneing, get on board (no really), but this is really the only hard technical reason: Address space.

rob.rice

doing things like unpacking bzip2 tar files running .configure files is amazingly fast compared to a 32bit system
a new kernel builds in half the time it did on a 32 bit system
I run slack so I install every thing from source any way the only non FOSS I use is the flash player
(and I would like to dump that it might be spyware )

bendib

NO!!! 32 bit can have a PAE kernel which lets you address more than 4GB of RAM, just install a 32 bit distro, besides, not all 64 bit distros have great support for 32 bit apps.

jhwilliams

PAE introduces trouble with some drivers. Also, it adds overhead. It's sort of a kludge to the problem, imho. It's like reserving the rfc1918 ip ranges while waiting for ipv6 to take over. I don't know, I think 32 bit anything are pretty ridiculous this day in age. ....

It's like, almost 2010.