Microsoft believes Windows 7 will be the tipping point for 64-bit. DailyTech heard over 25 percent of Windows Vista installations in the US at the end of 2008 were 64-bit, and Microsoft thins the majority of Windows 7 installations will be 64-bit.

Jon DeVaan, Senior Vice-President of the Windows Core Operating System Division, agrees. "From our point of view we believe that we have accomplished the tipping point in terms of 64-bit adoption. Now, this happened to a large degree because memory prices are coming down, and another dynamic that we've seen in the United States is that the retail channel is looking to use RAM upgrades as a way to boost margin. So what that means is that 64-bit machine run rate is increasing rapidly, and that means our ability to support those 64-bit machines fully in the broad ecosystem is a really important thing."

Any PC with 4GB of RAM or more must use a 64-bit installation of Windows in order to address the full amount of RAM. Typically a 32-bit installation would recognize a maximum of 3-3.5GB of RAM.

Instead of purchasing a 32-bit version and then having to change to 64-bit later when they purchase more RAM, many are choosing 64-bit at the start. Over 75 percent of Windows sales are based on OEM installations of new computers. The majority of Core i7 platforms are also using 64-bit operating systems, due to the triple channel memory setup using more RAM.