[ Solved ] Should I install 32 bit Linux distro or 64 bit?

[way12go]

If you have 32 bit pc then install 32 bit os, if you have multi core processor and or more than 3 GB RAM then use 32 bit PAE kernel/distro.

If you have single core processor and less than 3 GB RAM then use 32 bit non pae kernel.

If you have more than 3 GB RAM and if your system supports 64 bit then install 64 bit distro - 64 bit kernel

If I search on Internet for minimum requirements to install a 64-bit operating system, Microsoft and allied forums recommend 4 GB RAM as the minimum criteria.



The 4G minimum has nothing to do with the requirements of the OS, it is about efficiency. 32 bit systems, by nature the address values needed to talk to the memory being shorter, are actually more efficient up to a point.

32 bit systems can only address up to 4G of memory at a time. On modern linux kernels, this limitation is per process, so even a 32 bit OS can use more RAM but it accomplishes this by having each application only address up to some 4G block partitioned off from the whole stash.

Where 64 bit comes in is that it can offer processes the ability to address the entire system memory at once, allowing memory hungry things more than 4G if they need it. However it comes with a trade off. Since it uses more bits to save and handle addresses, the machine code gets bigger and runs just a tad slower.

Hence you can run a 64bit OS on 2G just fine, but it doesn't really make sense to because a 32bit OS is likely to be faster on the same system. Even when you cross the line into larger RAM, it is still possible that a 32 bit system will be faster because it is rare for any individual process to need that much RAM, more often you want to run lots of processes that all use some piece of the RAM.

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http://unix.stackexchange.com/questions/12467/hardware-to-install-64-bit-os

[way12go]

Enabling Physical Address Extension - PAE

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https://help.ubuntu.com/community/EnablingPAE

PAE (Physical Address Extention)

Physical Address Extension (PAE) is a feature to allow (32-bit) x86 processors to access a physical address space larger than 4 gigabytes. This includes RAM {Random Access Memory} and memory mapped devices.

Sometimes referred to as PAE-Highmem.

When to use a PAE version

If the (32-bit) computer has-

    more than 4GB RAM, then the PAE version is required to be able to access the whole memory.


        4GB or less RAM, then using the PAE version may be still possible/desirable. This is because of the No Excute feature (see below). Note, however, there may be a performance penalty using PAE (see Related Webpages).


No Excute

PAE is not only more physical address space but also important for the "no execute" feature which disables execution of code that is marked as non-executable.

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http://puppylinux.org/wikka/PAE

Non-Executable Memory

Most modern CPUs protect against executing non-executable memory regions (heap, stack, etc) to help block the exploitation of security vulnerabilities. This feature is called either "eXecute-Disable" (XD) or "Non-eXecute" (NX) or EDB (Execute Disable Bit), depending on your BIOS manufacturer.

In reading the system's /proc/cpuinfo file, the first flags line will include nx if the BIOS is not disabling the CPU feature, and the CPU is actually NX-capable. Nearly all 64-bit CPUs are NX-capable. If the flags line contains pae, usually the CPU will support NX:

    grep ^flags /proc/cpuinfo | head -n1 | egrep --color=auto ' (pae|nx) '

In a Dell laptop BIOS, look under "Security" / "CPU XD Support": it should be set to "enabled". In an American Megatrends BIOS, look under "CPU Features" / "Execute Disable Bit": it should be set to "enabled". Some BIOS manufacturers have released firmware updates for their BIOS to allow enabling NX (e.g. Lenovo IdeaPads) so make sure to install the latest BIOS if the NX option is missing.

In Samsung Netbooks (namely N140) enter with F2 the Bios and go to "Advanced" and set "EDB (Execute Disable Bit)" to "enabled".

On Ubuntu 10.04 and later, you can check if your hardware is expected to have NX available by running the command:

    /usr/bin/check-bios-nx --verbose

As far as making use of the CPU feature once it's not disabled in the BIOS, it will automatically be used if you're running a 64bit kernel. If you're using 32bit, you can start using it if you install the -server or -generic-pae flavor of the 32bit kernel. As a bonus, you get to address all your physical RAM if you do this too (since the "PAE" mode is the kernel mode that allows NX to work). In Ubuntu 9.10 and later, if you run 32bit kernels without PAE, you will still have the partial NX emulation. It is required that you use PAE if you want true NX support.

If you believe you are incorrectly getting the boot-time warning, please open a bug report against the cpu-checker package, or disable the check by removing the motd module: sudo rm /etc/update-motd.d/20-cpu-checker

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https://wiki.ubuntu.com/Security/CPUFeatures

For a 32-bit kernel, what are the pros/cons of PAE vs. non-PAE?

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http://askubuntu.com/questions/151068/for-a-32-bit-kernel-what-are-the-pros-cons-of-pae-vs-non-pae

[way12go]

32-bit and 64-bit

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https://help.ubuntu.com/community/32bit_and_64bit

Which is Better - 32 or 64 Bits?

If you are doing heavy work where you have started to hit the 4GB memory barrier, then 64-bit is for you. Certain intensive tasks such as encoding video or audio also run significantly faster on 64-bit operating systems (NOTE: this is implementation specific).

Phoronix has done some testing (2009), comparing 32bit/PAE/64bit, and this seems to indicate that 64bit performs better than 32bit in almost all cases.

Early 64-bit adopters were plagued by incompatibility problems (most noticeably Java and Flash), however most issues have now been resolved.

Some applications such as Flash do run slower in 64-bit mode, however work continues to improve on this.

Other platforms which also come in 32 and 64-bit flavours may experience more problems especially due to a lack of 64-bit device drivers as incompatible user application. As Ubuntu is entirely open source, this is not the case as all hardware supported by Ubuntu works equally well in 32-bit and 64-bit environments. The same applies to open source user applications as well.

Which Should I Choose?

Unless you have specific reasons to choose 32-bit, we recommend 64-bit to utilise the full capacity of your hardware.

32 or 64 bits on an Atom with 1gb of RAM?



As you can see, 64-bit uses double the memory just sitting at the desktop. Double! A third of a GB just idling is quite substantial if you only have a GB such as the atom being discussed here. Maybe there is something to be said for 32-bit on a low-hardware platform.

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http://ubuntuforums.org/showthread.php?t=1563993&page=3

[way12go]

How to decide if you should use 32bit or 64bit

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http://howtoubuntu.org/how-to-decide-if-you-should-use-32bit-or-64bit-ubuntu

Now, Canonical recommend 64bit for both 13.10 and 12.04.3, unless you have 2GB of RAM or less.

[pavroo]

It can be interesting I think:
1. VMware Player dropped off 32 bit version of it.
Version 7 of the player is for 64 bit machines only.
2. The latest version of Opera web browser 26 (stable) is for 64 bit systems (Linux).
If software makers will stop developing their products for 32 bit systems - the answer should be clear.

[py-thon]

One more aspect:
A 32-bit-Linux can only use 3 GiB of RAM for any single process (=program). So even if Linux's 32-bit-PAE-kernel supports up to 64 GiB and the motherboard supports more than 4 GiB RAM as well any hungry process will never be able to use more than 3 GiB, regardless of the amount of RAM installed.

[way12go]

Upto 2-3 GB RAM 32-bit non PAE is good for linux.
For Windows because of virus infections 2-3 GB RAM 32-bit PAE is must as PAE gives support to it, making sure they are not executed in memory.
More than 3 GB RAM 64-bit is must.

32-bit is slower than 32-bit PAE if RAM is more than 3 GB else 32-bit non PAE is correct.

More RAM, more than 3 GB RAM then 64-bit is better than 32-bit PAE.

If RAM is less than 3 GB then 64-bit will slow the distro or OS.

I must say there are two options for Windows OS - 32-bit PAE if RAM 2-3 GB and 64-bit if RAM more than 3 GB.

And for Linux PAE is not required if 64-bit support is available and RAM is more than 3 GB.

If you use linux and have less than 3 GB then go for non PAE 32-bit OS.

Just use Sparkylinux 32-bit non PAE if RAM less than 3 GB

Just use Sparkylinux 32-bit PAE if RAM more than 3 GB and if and only if 64-bit support is unavailable.

Just use Sparkylinux 64-bit if RAM more than 3-4 GB and 64-bit is supported.

[bobw]

Hi.  It looks like I want the non-PAE 32-bit.  Could you please tell me how to select this in SL3.6 Xfce?  The Download page seems to only have a choice of 32 or 64-bit - no mention of PAE.

[pavroo]

All the 32 bit versions of Sparky are non-pae.

[bobw]

OK.  I can see now, looking back at the earlier part of the thread, that PAE is an extension that has to be enabled.  Thanks pavroo for your very quick response.

[way12go]

Why You Should Probably Use the 64-bit Edition

At this point, the kinks are worked out — Flash works, it's easy to install 32-bit software, bugs aren't common, and you probably have a 64-bit CPU. If you're on the fence, it's time to take the dive and use the modern version of Ubuntu.

    Performance: Phoronix has taken a look at the performance difference between the 32-bit and 64-bit editions of Ubuntu 13.04. They found that the 64-bit edition of Ubuntu had superior performance in real-world benchmarks.
    UEFI Compatibility: The 32-bit edition of Ubuntu doesn't work with the UEFI firmware found on recent computers that come with Windows 8, so you'll need to install the 64-bit edition of Ubuntu on them.
    Memory and Security Features: The same memory and security factors we mentioned for Windows 7 also apply to Linux. If you want your system to have the ability to assign more memory to individual processes and use the latest low-level security features, you'll need the 64-bit edition of Ubuntu.

The main problems with 64-bit editions of Linux have been solved, so it's a good time to switch to the 64-bit version.

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http://www.howtogeek.com/165144/htg-explains-should-you-use-the-32-bit-or-64-bit-edition-of-ubuntu-linux/