If I get a PC with a 64 bit processor, I can get a promo copy of XP
Professional 64 bit edition.
  What sort of benefit would I see from running this version of XP?
  Faster overall performance?  Less bogging down when the hard drive
gets a bit busy?

Greetings!
The question of what kind of benefits you will see from a 64 bit
processor/operating system really depend on what kind of work you do
on your PC.  The big advantage a 64 bit system has over a 32 bit one
is the ability to handle math computations better.  For educational
institutions, corporations or anyone doing large amounts of
calculations/processing this translates into a decent block of time in
savings.  The average PC user on the other hand will only see a slight
upgrade in performance.

Microsoft has a web page set up here which lists in their opinion the
top 5 reasons to get Windows XP Professional x64 Edition

http://www.microsoft.com/windowsxp/64bit/evaluation/top5.mspx


There is a potential downside to upgrading to xp 64.  In my research I
came across a number of people reporting compatibility problems with
programs such as Adobe Acrobat and Windows Media Player.

The bottom line is that 64 bit processing is definitely the direction
the industry is heading.  While you may not see an immediate increase
in performance as more programs come out which are written to take
advantage of the 64 bit architecture you will probably begin to see
real speed increases. Until then you may have to suffer through some
problems as the bugs and compatibility problems are worked out.


Links you might find interesting...

The difference between 64 and 32 bit processors
http://www.softwaretipsandtricks.com/windowsxp/articles/581/1/The-difference-between-64-and-32-bit-processors

Microsoft XP 64-Bit Edition
http://www.microsoft.com/technet/prodtechnol/winxppro/evaluate/xp64ovw.mspx#EFAA

Hope this answered your question.  If you have any questions or need
something cleared up please request a clarification before rating my
answer and I'll be happy to see what I can do.

Best,
djbaker-ga


Search Strategy:

xp 64 benefits
://www.google.com/search?q=xp+64+benefits&hl=en&safe=off

64 bit processing explained
://www.google.com/search?q=64+bit+processing+explained&hl=en

benefits windows 64 over windows xp
://www.google.com/search?q=64+bit+processing+explained&hl=en

Nicely done - thanks!

Forget 64-bit Windows XP... I have AMD FX-51 and FX-53 but will not be
upgrading to 64-bit Windows XP until I find 64-bit programs that I
need/want.  64-bit Windows will run regular (32-bit programs such as
games)SLOWER than in 32-bit Windows.

Reasons to forget 64-bit Windows XP Pro

1. You need to install 64-bit drivers (which are rare)

For ALL of your hadware, you will need to install a driver made
specifically for use in 64-bit Windows XP.  Most hardware
manufacturers do not offer such drivers at the moment.  (Graphics
card, PCI cards etc.)

2. You don't have any 64-bit applications

Only the 64-bit applications (Do you have any? I don't think so.) will
run faster(they won't run in 32-bit) on Windows 64-bit edition. 
32-bit applications (I'd say 99.99999% of all programs made for
Windows XP)may run just fine but statistics show that they will run
slightly slower on 64-bit enviroment. 16-bit applications will not run
at all on 64-bit enviroment.

Not many software companies are developing 64-bit version of their
program at the moment.  They are waiting for Intel to release their
64-bit processors because AMD's market share is about 16-17% (2004)
and about half of those numbers are for the Athlon XP which is 32-bit
only.  And how many owners of AMD64 are using 64-bit Windows? I'd say
less than 5%. Why would software developers create programs for 64-bit
Windows when there are less than 0.1% of Windows users using or
thinking of upgrading to 64-bit?  Wait a year or two, see how the
software market for the Windows 64-bit develop.

3. Beta-versions and early release versions are full of bugs and issues.

Microsoft's Windows XP 64-bit Edition is being given out for free to
those who already own Windwos XP Professional Edition.  Why? Because
they need people to test their product for bugs and errors.  Remember
Windows 95? At the beginning it had so many bugs and issues; it will
be the same for Windows XP 64-bit edition.  Why would Microsoft give
you something for free?  Answer is: They won't.

4. Microsoft is releasing their NEW operating system called "Longhorn"
soon.  This will be the true 64-bit Windows everyone will be using.
Wait until then, Microsoft will have solved many of the bugs and
issues associated with 64-bit enviroment by then.

5. AMD Athlon 64's true advantage is that it works with 32-bit and
64-bit operating systems.  Just because you have a 64-bit compatible
CPU, you don't have to upgrade to 64-bit Windows to use it.

Windows XP Professional 64-bit Review by C|NET
http://reviews.cnet.com/Windows_XP_Professional_x64_edition/4505-3672_7-31346186-2.html

32-bit versus 64-bit
http://news.softpedia.com/news/Windows-versus-Windows-or-32-bit-versus-64bit-1349.shtml

Windows 64-bit Drivers Check list
http://www.microsoft.com/whdc/driver/kernel/64bit_chklist.mspx

If users do not accept a reasonable upgrade path software will not be
ported to 64 bit as quickly as they should.  The comments from xm177e2
are somewhat misleading and really do not illicit a great technical
strategy.  If we all followed their advice we would still be using
16-bit (or even 8-bit) DOS applications.

Now for some educated advice from someone who has been using Windows
XP 64 Bit Edition for some time now.

Myth 1 (Drivers are rare)
This has gone from truth to myth in the last 3 or 4 months.  (Time is
no excuse for xm177e2 because as of May there was decent support for
64 bit.)
AMD provides an extensive list of drivers at:
http://www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_%202252_869_875%5e10454,00.html?redir=IEGFC07

Myth 2 (You don't have any 64-bit applications)
Well this is just down right embarrasing that the poster would say
this.  The fact is that you CAN'T have any 64 bit apps right now, how
would they run on a 32 bit system.  We can assume the misleading
subtopic is in reference to the lack of quantity of 64 bit
applications in the field.

This is true, however this is no reason not to upgrade from a 32 bit
operating system to a 64 bit operating system.  AMD64 and the EM64T
(intel) processor (that have both been out for almost a year now) are
'transitional' processors.  They are intended to facilitate the
transition of end users from a 32 bit platform to a 64 bit platform. 
Windows XP 64 bit edition supports BOTH 32 bit and 64 applications so
that users can transition their application library slowly and
sensibly.
http://www.microsoft.com/windowsxp/using/64bit/russel_exploringx64.mspx

There are, however, 64 bit applications already in existance today and
more are on the way.  Internet Explorer is 64 bit, Mozilla (netscape)
/ Firefox is 64 bit (still in beta but slated for release soon).  Game
developers will quickly adopt the 64 bit market because of the
mathamatical performance gains and the increased memory
addressability.

There is a performance hit to run a 32 bit application on a 64 bit
version of windows, however it is transparent to the user and in most
cases a minute difference that is not detectible to the user.
http://www.devx.com/amd/Article/20342

The majority of the complaints I have heard in the field with 64 bit
early adopters is related to video card driver performance slowing the
system.  Luckily with the RTM (Final Retail) release of Windows XP 64
Bit Edition many of these problems went away.

Myth 3 (XP 64 Bit is in beta) Beta-versions and early release versions
are full of bugs and issues

Windows XP 64 Bit is available now.  Microsoft provides free 'early
adopter' versions of their software so that the development community
can rev. their software for the new operating system so that once the
OS is released for retail consumption there will be some cool apps
available to use on it.

Windows XP 64 bit edition is released and is NO LONGER a BETA product.
http://www.microsoft.com/windowsxp/64bit/default.mspx

Microsoft is allowing users of 64 bit hardware that have 32 bit
versions of XP to upgrade and convert to the 64 bit version for free. 
Indstead of casting a negative light on this why can you not see this
is a noble effort.  They are allowing people that have already paid
for a lesser version of XP to get the latest and greatest OS that was
created specifically for their hardware and they are not going to
charge the user for it.  Now if Microsoft had charged for it 'xm177e2'
would have bashed Microsoft for charging users to upgrade to the OS
that they should have rightfully had when they bought the pc...but
Microsoft held back to make sure the OS was stable before letting it
out the door.

4. Microsoft is releasing their NEW operating system called "Longhorn"
soon.  This will be the true 64-bit Windows everyone will be using.
Wait until then, Microsoft will have solved many of the bugs and
issues associated with 64-bit enviroment by then.

Longhorn will not be released until late 2006 possibly even in 2007. 
Longhorn is not an OS specifically designed to run at 64 bits whereas
Windows XP 64 bit is specifically designed and engineered for a 64 bit
platform.  Longhorn is a complete OS rewrite including many technical
advances that push the envelope of OS technology.  Telling a user to
avoid a 64 bit build of an existing OS that has aged well for the last
5 years is insane.

I recently tried switching to a XP Pro x64--and was horrified. 
xm177e2 was pretty much right on target--and still is on target 5
months later!

1.  Drivers
While there are drivers for most mainstream system components, support
for printers and peripherals is still quite poor.  For example, most
HP printers either don't have drivers--or only have beta drivers:
http://h10025.www1.hp.com/ewfrf/wc/document?lang=en&lc=en&cc=us&docname=c00365046&lang=en&cc=us
.  Microsoft, themselves, still do not have a working version of
IntelliPoint or IntelliType (the mouse & keyboard will work, but wont
have any advanced features).  If you have other Microsoft hardware,
you might be completely out of luck.  They still don't have drivers
for most of the other hardware they sell (fingerprint scanner,
joystick, etc.)!  You'll be fine if you have all mainstream hardware
in your computer, but if you have some odd hardware or add-on devices,
you might be out of luck.

2.  The percent of hardware that works just fine is probably lower
than 99%.  Anti-virus is still a major problem.  There are a few to
choose from, including a free one from avast... but most vendors
either don't make an x64 version yet or don't make home versions (ie:
Symantec).  The other programs that don't work well with X64 versions
of Windows usually tie into the shell.  For example, context menus for
WinZip and other compression programs don't work (there is a sloppy
workaround for WinRar).  Microsoft's own Windows Media Player doesn't
have regular shell functionality, so you cant use the taskbar toolbar
view!  Virtual CD drive software isn't there yet, either... the main
vendors don't support x64.  Some small vendors are trying to fill
these various markets with their own software--but most of it is low
quality, lacking features or unreliable.

Yes, you can use a 64-bit version of Firefox or the 64-bit IE built
in... and they'll work great as long as you don't need to tie into
third party plugins.  Have websites that use Flash?  Forget it...
you'll be back to your 32-bit web browser.  It is no fun switching
between web browsers every time you run into a site that uses flash.

3.  Windows x64 isn't in beta--but with all the serious limitations
with shell integration, anti-virus support, hardware drivers and lack
of 64-bit applications it might feel like it sometimes.  I don't think
its a problem with the quality of Windows codebase, it has more to do
with the fact you are trudging through territory that most software
developers simply don't care about.

4.  Vista (Longhorn) is still over a year away--and the maturity of
the x64 platform will start to show.  You can use XP x64 now and help
put pressure on vendors to get things working now... and those who
adopt with Vista will appreciate your efforts in making THEIR
transition more painless.

I hope you find your x64 transition pleasant and painless like imedia
paints it out to be.. but based on my experiences and those of my
peers, I suspect you've already ran into a lot of the challenges I've
mentioned.  Unless you like sorting through compatibility issues and
trying new software, I'd hold off for Windows Vista.

I have noticed that the more 32bit Software I installed on the system
the slower the system goes.
For example, Nero Express is running fine but when I switch to other
programs from Nero Express the whole system acted up and need to wait
around 30 seconds to 1 minute before I can switch to other programs.
This does not happen when I was using 32bit Windows. Performance on
games such as World of Warcraft does not make any difference in 64bit
Windows.

Firefox 32bit is slow at loading websites compared with 32bits Windows.
If you are a tinker, sure go install Windows 64bit. But personally I
am going back to Windows 32bit and wait until then...