32 bit vs 64 bit

To make it a little less complicated they made the adv/dis adv in a table. Please visit microsoft link to see the table.

Pros and Cons of a 64 bit system:

* You can address much more than 4GB of memory, which is ideal for avid gamers, CAD, video editors and heavy multi-taskers. However, any 32 bit software you use will still be restricted to 4GB memory – you need a 64 bit CPU, OS and applications to take full advantage of the extra RAM.
* 16 bit applications will no longer run. Although this is unlikely to be a problem, if you use very old software (from the Windows 3.1 days!) then it will not work under a 64 bit OS.
* Existing 32 bit drivers no longer work.If you have older or poorly supported hardware you may find that it can no longer be used. Got a 7 year old scanner that just about works in Vista? You may not be able to get it working in 64 bit Windows 7.
* Unsigned kernel-mode drivers no longer work. Along with the issue above, the inability to run unsigned kernel mode drivers will cause problems for old hardware. (There is reportedly a way to bypass this check).
* Running some 32 bit applications on a 64 bit OS could actually be slower. The additional overheads in running 32 bit software in 64 bit mode could cause a slight degradation in performance. It will take some time for 64 bit software to become the norm. [http://www.w7forums.com/windows-7-64-bit-vs-32-bit-t484.html]

now after reading this you want 64 bit now right?!

But wait you have to check first if your Laptop or PC has 64bit processor.

How do I tell if my computer can run a 64-bit version of Windows?

To run a 64-bit version of Windows, your computer must have a 64-bit-capable processor. To find out if your processor is 64-bit-capable, do the following:

1.

Open Performance Information and Tools by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Performance Information and Tools.
2.

Click View and print details.
3.

In the System section, you can see what type of operating system you're currently running under System type. Under 64-bit capable, you can see whether you can run a 64-bit version of Windows. (If your computer is already running a 64-bit version of Windows, you won't see the 64-bit capable listing.)
[source]

In Other Windows OS Just view System


If it's Intel, certain Pentium 4s and pretty much everything past the Pentium D (except the Core Duo) is capable of running a 64-bit OS.
As for AMD, anything with 64 appended to its name should be good (i.e., Athlon 64X2.)

64-bit support came with the Core 2 Duo.[source]

mine is
Intel® Core™2 Duo Processor T5500 (2M Cache, 1.66 GHz, 667 MHz FSB)[link]

so yey! I can use my 4Gb ram! (32bt can only use 3-3.5MB of ram)



SUMMARY
If you are home user with less than 3Gb ram use 32 bit!
If you are an IT professional who needs all the RAM(4GB to 128GB RAM) in the world or a rich home user with so many ram then use 64 bit!