When you buy Windows 7, you have a choice between a 32-bit and 64-bit version of the operating system. You may have to make that choice at purchase or at installation, and the right choice will depend on your current hardware and, to a lesser extent, how you use your PC.
32-bit, 64-bit and 32/64-bit Versions
Windows 7 is available in both a 32- and 64-bit edition. Most retail versions of the OS have two discs, one for 32-bit and one for 64-bit. If you purchase a license, then that license can be for both versions but will usually be for one or the other. The safest option may be to purchase an edition with both versions, but ideally you should choose a version and then buy Windows 7 accordingly.
Choosing an OS Version Based on Hardware
The 64-bit version of Windows requires a CPU that supports a 64-bit mode. When you could first buy Windows 7 at retail, well more than half the CPUs at market did not support 64-bit. At the time of this writing, nearly all CPUs are 64-bit. You can run the 32-bit version of Windows whether you have a 32- or 64-bit CPU. Keep in mind that the 64-bit version also requires 2 GB of RAM. If you have less than that and are unwilling to update, then choose 32-bit.
64-bit Windows Won’t Run on a Non-64-bit CPU
The 64-bit version cannot install on a CPU that doesn’t have a 64-bit mode. If buy Windows 7 with both versions included, then you can simply swap in the other disc or, in some cases, have the installer automatically choose 32-bit. If you choose 64-bit only, however, you’ll be stuck with a non-working OS.
Why Choosing 64-bit Windows Makes Sense
Moving forward, most software and hardware are configured for a 64-bit environment. Upgrading makes sense because it will be the more stable, future-proof environment. A 64-bit system can also make use of significantly more RAM, and this will become more useful as programs are increasingly able to use more memory. A 64-bit system also allows for better performance; however, this performance increase is generally not something that the average user will be able to sense in real-world applications.
Why Choosing 64-bit Windows May Not Make Sense
If your CPU does not have a 32-bit mode, then 64-bit Windows does not make sense. If your PC has less than 2 GB of memory and you cannot or will not update, then 64-bit Windows does not make sense. Finally, there is the issue of compatibility. Some 32-bit programs will not work or will be unstable in 64-bit environments. Keep in mind that this issue is rare because of software updates and the compatibility mode in Windows, but if you have a specific program that you rely on, then you should ensure compatibility before making this decision.