How do I know that my CPU supports 64bit operating systems under Linux?

Question

How can I find out that my CPU supports 64bit operating systems under Linux, e.g.: Ubuntu, Fedora?

Solution 1

Execute:

grep flags /proc/cpuinfo

Find 'lm' flag. If it's present, it means your CPU is 64bit and it supports 64bit OS. 'lm' stands for long mode.

Alternatively, execute:

grep flags /proc/cpuinfo | grep " lm "

Note the spaces in " lm ". If it gives any output at all, your CPU is 64bit.

Update: You can use the following in terminal too:

lshw -C processor | grep width

This works on Ubuntu, not sure if you need to install additional packages for Fedora.

Solution 2

I think the easiest way is by:

lscpu|grep "CPU op-mode"

Solution 3

If your CPU is a 64bit one (x86-64), you can use it with a 64 bit OS.

Here is a list of 64bit CPUs: http://en.wikipedia.org/wiki/64-bit#Current_64-bit_microprocessor_architectures

Solution 4

via this command dmidecode -t processor we can check the processor capability.

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Comments

[Gilles 'SO- stop being evil']

possible duplicate of How come I installed Ubuntu 64 bit on a Pentium 4 machine?

[Gilles 'SO- stop being evil']

More generally, see What do the flags in /proc/cpuinfo mean?

[ctrl-alt-delor]

Once you have checked the flags, then install the kernel package. Debian and Ubuntu, can run a 64bit kernel with a 32 bit userland. Installing the kernel is quick. Do not remove the old 32bit one, as you may need to go back to it.

[trusktr]

This answer is the best. It shows you an explicit "32-bit" or "64-bit". I don't see why people choose the other answer over this one. You don't even need to grep anything. Just doing lscpu is so simple. If they don't have the lscpu command then I could see why they voted for the other one.

[trusktr]

This is the ultra slow way, and not guaranteed to give you an answer.

[Clifford]

@trusktr: Yes. but all the other ways require Linux to be installed already. Not much help if you have an old Win32 machine and want to know if it will run a 64 bit *nix OS

[Benjamin Goodacre]

The command that is the most portable across the largest variety of platforms is arguably the most useful.

[ELLIOTTCABLE]

Same here. Found this useful, not having a running OS on the system in question to test it with.

[dstonek]

I got '32-bit, 64-bit' What does it mean?

[peterh]

Afaik it won't work if "lm" is the last flag in the line. :-)

[Ikem Krueger]

It is a 64-bit machine running in 32-bit mode.

[sondra.kinsey]

That outputs a ton of other stuff, and splits "64-bit capable" on a different line than it's vague heading ("Characteristics"), so it's difficult to parse.