How to identify 64 bit processor with cat /proc/cpuinfo

Question

I have intel celeron d 3.06ghz processor . Now I am using 32 bit Ubuntu and I wish to upgrade to 64 bit Ubuntu if my processor allow. My doubt is how to identify 64 bit processor with cat /proc/cpuinfo command. it shows

clflush size : 64

Does my processor support 64 bit OS ?

Solution 1

Use the lscpu command.

32bit example output:

$ lscpu
Architecture:          i686
CPU op-mode(s):        32-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    4
Core(s) per socket:    1
Socket(s):             1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 26
Stepping:              5
CPU MHz:               2260.998
BogoMIPS:              4521.99
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K

64bit example:

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
CPU(s):                4
Thread(s) per core:    1
Core(s) per socket:    4
CPU socket(s):         1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 23
Stepping:              6
CPU MHz:               2327.533
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              6144K

Solution 2

The flags section will contain lm if you have a Intel 64-/AMD 64-capable CPU. Other 64-bit architectures should have similar flags that you can look for.

Solution 3

To know if the installed Ubuntu is of 32 or 64 bits:

a) getconf LONG_BIT

b) uname -m

If it shows i686 or i386 it means 32 bits. If it shows x86_64 it means 64 bits.

If the CPU is of 32 bits Ubuntu must be of 32 bits. If the CPU is of 64 bits it can work in 64 or 32 bits. So we can choose: Ubuntu can be of 32 bits or of 64 bits.

To know if the CPU is of 32 or 64 bits:

a) grep -w lm /proc/cpuinfo

If we see lm in red is of 64 bits. Otherwise is of 32 bits.

b) sudo lshw | grep "description: CPU" -A 12 | grep width

It says clearly what we want to know.

Comments

[imz -- Ivan Zakharyaschev]

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

[Paulo Scardine]

AFAIK uname shows only information about the compiled kernel. Of course you can have a 32bit kernel instaled in 64bit hardware, but not the other way.

[KamikazeCZ]

I know, I changed it immediately. Now it should be OK.

[Paulo Scardine]

-1: bad karma - you just copied from the other answers.

[KamikazeCZ]

Well... I didn't but do your best.

[glglgl]

First part is obsolete. OP says "Now I am using 32 bit Ubuntu".

[Paulo Scardine]

lsb_release -a works for LSB compatible distros.

[Daniel Alder]

For those who are interested: This is what it shows if you are running a 32bit OS on a 64bit CPU: Architecture: i686 / CPU op-mode(s): 32-bit, 64-bit