Taking the mystery out of 64-bit Windows

If you’re shopping for a new computer, chances are you already have enough to consider without wondering whether you should buy a computer with a 32-bit or 64-bit version of Windows 7.

There’s no need to fret. For most people, there’s little reason to think about this choice when you’re making your next computer purchase. That’s good, since many people don’t understand the difference between a PC running a 32-bit or 64-bit version of Windows, and the version they choose won’t make a big difference in most cases.

Some power users prefer a 64-bit version of Windows. There’s no mystery there. A computer with a 64-bit version of Windows can use more memory—4 GB (gigabytes) or more—than a PC with a 32-bit version of Windows, which is limited to about 3.5 GB or less. (Even if a PC comes with 4 GB or more of memory installed, a 32-bit version of Windows can only use about 3.5 GB of that memory.)

With more memory, you can keep more files and programs open at once without slowing down your computer. But having more than 3.5 GB available usually won’t matter unless you really keep a lot of things open at once (more on that later).

Picture of the System control panel
You can check System in Control Panel to see if your PC is running a 32-bit or 64-bit version of Windows.

Real world differences versus spec sheet differences

Because prices have fallen so much in recent years, many new computers now come with 4 GB of memory—even budget models. A lot of manufacturers have started installing a 64-bit version of Windows on their PCs by default to make sure buyers are able to use all of the memory they paid for. Some are even shipping all of their new computers with a 64-bit version of Windows, and doing so even though it’s difficult to tell the difference between a PC using 4 GB and 3.5 GB of memory.

In actual everyday use, most people probably wouldn’t notice a difference between a computer using 3 GB of memory and one using 6 GB. So who might notice the difference? Well, if you’ve ever known anyone who keeps a couple dozen e-mail messages, a dozen programs, and a half dozen other items all open at the same time—while playing videos—then you get the idea.

Having more than 4 GB of memory available can make your computer more responsive if you like to keep everything running at once and rarely close anything.

Serious PC game players might also be interested in a PC running a 64-bit version of Windows. Games are some of the most hardware-intensive programs you can run on any computer, with their rich graphics, sound, and interaction capabilities.

The 64-bit version of Windows 7 Ultimate, Enterprise, and Professional editions can all use up to 192 GB of memory (far more than even a power user would typically need), making them ideal for specialized computing tasks that require enormous amounts of memory, such as rendering 3D graphics.

Most of the performance gain in computers running a 64-bit version of Windows comes from this added memory, combined with a powerful 64-bit processor able to use that extra memory.

But for most people who just keep a few programs running at a time, 4 GB or more of memory offers no tangible benefit over a computer with 2 GB of memory and a 32-bit version of Windows.


  • Server computers—such as computers used to run websites or large corporate networks—can especially benefit from more memory. But they have their own powerful operating system—Windows Server—which also comes in a 64-bit version and can use even more memory than Windows 7.

32-bit versus 64-bit processors

So what do you need to run a 64-bit version of Windows? That’s no mystery either. You need a computer with a 64-bit processor (also called an x64 processor, or CPU).

It’s not obvious from the names of most processors if they are 64-bit or 32-bit. If you want to know, you can check with the manufacturer or with the store selling the computer.

If you’re buying a new computer with Windows 7, it will most likely come with a 64-bit processor, although perhaps not a 64-bit version of Windows 7. This is where it gets a little confusing. Computers with a 64-bit processor can run either a 32-bit or 64-bit version of Windows just fine. So it doesn’t matter too much which version of Windows you install on most PCs with a 64-bit processor—unless you want to be able to use more than 3.5 GB of memory.

To find out if your current PC is capable of running a 64-bit version of Windows, download and install the Windows 7 Upgrade Advisor from the Windows 7 Upgrade Advisor webpage. This program will analyze your computer, create a report telling you if your PC can run Windows 7, and list any known compatibility issues, including whether you can run the 64-bit version of Windows 7. For more information, see 32-bit and 64-bit Windows: frequently asked questions.

Get a 64-bit version of Windows with a new computer

There’s no mystery when it comes to upgrading to a 64-bit version of Windows. You can’t upgrade from a 32-bit version of Windows to a 64-bit version. To install a 64-bit version of Windows on a computer already running a 32-bit version, you have to do a clean installation, which formats your hard drive and erases all of your files and programs.

That’s why most people who get a 64-bit version of Windows do so when they buy a new computer. (If you do plan to install a 64-bit version of Windows on a computer running a 32-bit version, be sure to back up all your files and other information first. You'll also have to manually reinstall your programs.)

What about cost? Are 64-bit processors more expensive than 32-bit processors? Not typically these days, although they used to be, and you can certainly find some computers with a 64-bit processor that are more expensive. The most common reason for this is the extra memory. If a computer with a 64-bit processor comes with more memory, it might cost a little more than a computer with a 32-bit processor that has less memory.

Windows doesn't add a cost factor, since the 32-bit and 64-bit versions of Windows both cost the same.

How to tell if you're running a 32-bit or 64-bit version of Windows

What if you’re not shopping for a new PC and want to know if your computer is running a 64-bit or 32-bit version of Windows? Since both versions look identical, you need to know where to look. The easiest way to tell is to check System in Control Panel.

To do so, click the Start button Picture of the Start button, click Control Panel, type System in the search box, and then click System. Under System, next to System type, you can see if your PC is running a 32-bit or 64-bit operating system.

32-bit versus 64-bit drivers and programs

If you’re running a 64-bit version of Windows, your computer needs a 64-bit driver for every piece of hardware installed on your PC or connected to it. For example, if you're trying to install a printer that only has a 32-bit driver available, it won't install in a 64-bit version of Windows. But the good news is there are tens of thousands of devices available today with 64-bit drivers, which Windows can automatically find and install for you.

For hardware makers to earn a "Compatible with Windows 7" logo, their hardware must have drivers for both 32-bit and 64-bit versions of Windows. If you see this logo, you don’t have to wonder if the hardware is going to work with the 64-bit version of Windows.

Unlike drivers, most programs designed for a computer running a 32-bit version of Windows will run fine on a computer running a 64-bit version of Windows. (Notable exceptions are antivirus programs.) However, most programs designed specifically for a 64-bit version of Windows will often run faster, especially if they involve intensive tasks such as editing high-definition video or operating a large database.

You can check the availability of 64-bit drivers and programs online at the new Windows 7 Compatibility Center. This can be useful if you’re considering buying a new printer, for example, and want to be sure a 64-bit driver is available before you buy it—or if you want to find out if there are 64-bit versions of your favorite programs.

The Windows Vista Compatibility Center also lists the availability of 64-bit drivers for thousands of hardware products, and tells you whether there are 64-bit versions available for thousands of programs.

There are other considerations when installing hardware and programs in a 64-bit version of Windows. For more information, see Understanding hardware and software for 64-bit versions of Windows.

Mystery solved

Now that we’ve solved the mystery of 64-bit Windows, you can see that 64-bit computing never really was much of a mystery in the first place. Nor does it have to be a dilemma for most computer users.

Whether you already have a PC with 64-bit processor or are thinking of buying one, the key is choosing the right version of Windows for the way you work or play. In most cases, it won’t matter if that’s a 32-bit or 64-bit version.