[mdlug] [Fwd: Re: [opensuse] 64 bit vrs 32 bit advantages speed etc.]

[Aaron Kulkis]

Peter Bart wrote:
> On Wed, 2007-10-31 at 09:58 -0400, Adam Tauno Williams wrote: 
>>>>> Has anyone run benchmarks on an identical system with 32 bit vrs 64 bit?
>> I haven't run "benchmarks", but I've run tests.  The plain and simple is
>> that for the *vast* majority of workloads 64-bit offers no noticeable
>> advantage, and usually a barely measurable difference.  I've even seen
>> 64-bit run slower than 32-bit, especially if your application deals
>> mostly with parsing and dealing with strings.
>>
>> The real advantage of 64-bit is a larger address space,  which most apps
>> just don't need.   It *might* be faster at some other things, like
>> context switching, but not necessarily so, and it is going to depend on
>> a myriad of other factors.
>>
>> A good rule is to run 64-bit if you have an app that can effectively use
>> a BIG address space, like PostgreSQL,  otherwise it probably isn't worth
>> the bother until everything is 64-bit (since doing the
>> this-is-32bit-that-is-64bit dance on a host is a pain).
> 
> Okay then, I need to ask a stupid question. I finally received the new
> laptop and it has a 64 bit processor.
> 
> Intel® Core™ 2 Duo Processor T55004
> o 1.66GHz, 2MB L2, 667MHz FSB with 64-bit
> • Mobile Intel® 945PM Express Chipset
> • Integrated Wi-Fi® compliant wireless LAN
> 
> Since it has that capability I was going to load the 64 bit version of
> opensuse, if for nothing more than to know that it's there. Will this be
> a hindrance to me, running openoffice, web browsers, VMWare? How about
> running a 32 bit copy of Vista in a 62 bit opensuse? Or will I simply
> not notice it? I'm not sure what you mean by the "dance on a host"
> statement.

First, I'll give you my relevant familiarity with
this issue: in the commercial sector, I administrated
machines with 64-bit OS installs as far back as 10
years ago.  At that time, there were three options:

1) buy 32-bit hardware, install 32-bit OS and run 32-bit code.
or
2) buy 64-bit hardware, install 64-bit OS and run ONLY 64-bit code.
or
3) buy 64-bit hardware, install 32-bit OS and run ONLY 32-bit code.

When AMD released the AMD-64 a couple years ago, a
fourth option became available:

4) buy 64-bit hardware, install 64-bit OS and run
    both 32-bit and 64-bit code.

I *believe* that AMD is the only CPU manufacturer
with a product that provides option (4)  -- they
MIGHT have licensed the technology to Intel (if
needed for 2nd-source obligations to secure one
or more government contracts), or not -- I really
don't know for certain.

               =-=-=-=-=-=-=-=

Now, for todays Linux situation... even if your
hardware allows option (4):

A lot of web-browser plugins do not yet have
64-bit versions....and a 32-bit plugin WILL NOT
run properly in a 64-bit browser.  Many people
who have 64-bit installations are complaining
that they can't view Adobe Flash content, and
other similar problems.

                =-=-=-=-=-=-=

Basically, the 64-bit platform is not yet ready for
general purpose computing -- it fulfills certain
niche areas (massive finite element analysis,
extremely large database operations, etc) but has
not yet been completed in many areas.

Even on AMD-64 chips, which can run 32-bit code
in a 64-bit platform (the only CPUs I know of which
are capable of doing this), there are currently
a lot of problems still.

Unless you have some bleeding-edge NEED for
64-bit code, my advise is to wait until this
mess is all sorted out -- it's probably going
to take another 12 - 24 months.  Personally, I
don't need the frustration, and NOTHING that I
do would benefit significantly from 64-bit install,
but a lot would be degraded significantly if I
were to go that route at this time.