32 or 64 bit?

[Loïc Grenié]

2009/12/4 Mr. Teo En Ming (Zhang Enming) <space.time.universe at gmail.com>:
>
>
> On Sat, Dec 5, 2009 at 12:45 AM, Nik N <niknot at gmail.com> wrote:
>>
>> I am about to install Ubuntu 9.10 on a laptop with a 64-bit AMD Turion.
>>
>> Can someone point me to a text that discusses the pros and cons of
>> using a 64-bit (vs. 32-bit) Ubuntu on it?
>> TIA, Nik N.
>
> I think there's no need to discuss pros and cons of 32-bit vs 64-bit. If you
> have a 64-bit machine, you should install a 64-bit OS.

     There is no need to install a 64 bit OS.

    There are pros and cons, I don't know all of them but here are
  some:

  - 64bit is better if you have a lot of memory, there are tricks
    in 32 bits to access a bit more than 4GB, but if you have
    (and need to access in one application) more than 3GB of
    RAM you will need a 64bit OS.

  - The 64bit mode of x86 processors has more registers, so
    that the execution is slightly faster.

  - The binary are bigger (because data tend to be bigger), so
    that you need a bit more space (not much) and execution
    can be slower (if you need to fetch more 64bit data where
    32bit would be enough).

   - Flash is still 32bit (the 32bit version works with 64bit
     browsers using a wrapper and there is a slightly buggy
     64bit version).

  As far as I can tell, if you do not have 8GB of RAM there
  are no fundamental reasons to go one way or the other.
  Personal experience: I've gone 64bit but I can't really tell
  the difference !

      I hope somebody else has good reasons to choose
  one over the other...

       Loïc