32bit vs 64bit Linux

[Brian Weaver]

If you have more than 4GB of memory, you must use a 64bit kernel or the OS
will not use the additional RAM over 4G.



On Fri, May 31, 2013 at 10:00 AM, Nathan England <nathan at nmecs.com> wrote:

> **
>
>
> Keith,
>
>
>
> You and I have discussed this in the past. I have always been a proponent
> of 32-bit over 64-bit because 32 is a little faster.If you have one or two
> GB of ram, then that is true. But if the computer has more than 2 GB of ram
> it will get some benefits of being 64-bit. But if your system has 4 GB or
> more, you will likely notice a speed difference. About a year ago, when I
> moved back to linux from windows, I went all 64-bit and I've not had any
> troubles.
>
>
>
> You may not notice a difference, but your kernel will be happier. The are
> three styles of kernels.
>
>
>
> (1) 32-bit kernels built for 1 or 2 GB of ram. These kernels do not have
> PAE enabled and are very fast. (PAE = Physical Address Extensions) meaning
> it allows to use more memory on a 32 bit system which really cannot use
> that memory otherwise. It's like fake 64-bit.
>
>
>
> (2) 32-bit kernels built for more than 2 GB of ram. These kernels have PAE
> enabled. I have read several articles now from people who have done tests,
> as well as some reputable websites, that agree that PAE enabled kernels are
> the slowest of the bunch. Addressing 64-bit memory space while operating in
> a 32-bit environment takes a lot of tricks and creates some over-head.
>
>
>
> (3) 64-bit kernels are the fastest in all tests performed. These do not
> play the PAE tricks as they are native and can address all memory space
> properly.
>
>
>
> You as a user may not notice the difference in how any of the kernels
> work, so it may be moot to you. But in the end, I would recommend you go
> 64-bit anyway.
>
>
>
> Nathan
>
>
>
> On Friday, May 31, 2013 09:28:01 keith smith wrote:
>
>
>
>
> Hi,
>
> Even though I have 64bit hardware I always install the 32bit version of
> Linux.  I do so because of the past discussions on this list that made me
> believe the 32bit OS was better because 64bit caching is actually slower
> due to the requirement that the cache be filled to a certain point before
> it is moved.  I think I recall something about the amount of RAM having
> some effect here also.
>
> Using a 32bit version over a 64bit version seems counter intuitive,
> however that is what I have taken away from these conversations about 32bit
> vs 64bit Linux.
>
> I'm using CentOS 6.x on a LAMP server that gets a low amount of traffic.
> However I may make the jump to Linux on my desktop this summer. (this will
> be my 3rd attempt to become M$ free except one VM so I can use IE for
> testing) I think all of my hardware is 64bit.
>
> So that begs the question, is 32bit better than 64bit or do I not
> understand the issue?
>
> Thank you for your feedback.
>
> Keith
>
> ------------------------
> Keith Smith
>
>
>
> --
>
>
>
>
>
>
>
> Regards,
>
>
>
> Nathan England
>
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> NME Computer Services http://www.nmecs.com
>
> Nathan England (nathan at nmecs.com)
>
> Systems Administration / Web Application Development
>
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>
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