Microsoft blogger Brandon LeBlanc reveals statistics on the 64-bit vs 32-bit Windows installed base and reports 64-bit is becoming the norm. However, a close look at the numbers reveals the adoption of 64-bit is still very poor. Nearly 7 years have passed since the introduction of AMD's Athlon 64, yet only 46 percent of Windows 7 installations are 64-bit.
Reasons why 64-bit adoption is so slow are plenty. There are few killer applications that require it, driver support isn't that great either, many netbooks are still 32-bit, and lots of corporations are reluctant to make the switch because 64-bit versions of Windows can't run old 16-bit applications.
A primary benefit of 64-bit Windows is the increase in addressable memory. This makes more “bits” available to Windows (the OS), which means more information can be “addressed” at once. 32-bit architectures have a memory ceiling of 4GB while the 64-bit architecture increases the memory ceiling to approximately 17.2 billion GB or RAM! Windows 7 is designed to use up to 192 GB of RAM (see SKU and OS comparisons here), a huge jump compared to limits with all 32-bit systems.
Essentially, 64-bit Windows allows your PC to take advantage of more memory to do more things. If you are like me and are running tons of apps, you can see a real difference in performance. Aside from the performance gains, there are also security enhancements and support for virtualization as well.
The reason for the jump in transition to 64-bit PCs can be attributed to a few things. The first is the price of memory has dropped over the last several years making it easier for OEMs to up the amount of memory in the PCs they ship. And most major processors in PCs today are capable of running a 64-bit OS. There are also more and more compatible devices and applications for PCs running 64-bit Windows 7– but I’ll talk more about this in a minute.