The 64 Bit Question

The 64 Bit Question


By now, most of you have heard of 64 bit computers, even if you do not have one. And some of you may even have one and not know it, because you're not running a 64 bit operating system. 64 bit processors are actually nothing new; 64 bit RISC CPUs have been in use since the 1990s, but they were used primarily for servers and very high end workstations. And you might be surprised to learn that IBM and Cray supercomputers of the 1960s and 1970s were based on 64 bit architecture. Only more recently, however, has the technology trickled down to the rest of us.

The more mature among us may remember the transition from the 16 bit Intel 8086 and 80286 processors to the 32 bit 80386 in the mid-1980s. If you are really getting up in years, you might even remember the 8 bit 8080 model that was used in game consoles and the early home computers in the late 1970s and early 1980s. But what do these numbers mean, anyway?

As you probably know, a bit is one binary digit (a 1 or 0). As an aside, in the standard x86 32 bit architecture, a group of 4 bits is called a nibble, a group of 8 bits is a byte, a group of 16 bits is a word, and a group of 32 bits is a double word or dword (now you know what that "DWORD Value" refers to in the registry editor). In the context of this article, the number of bits refers to the amount of data that a CPU can access in a single operation.

When you double the number of bits that can be accessed in a single operation, you make it possible for a computer to process information more quickly. This also affects the total amount of system memory (RAM) that a computer can reference. 32 bit machines can reference 232 (two to the thirty-second power) addresses, which is equal to 4 GB of RAM. That's the reason you're limited to that amount of memory on a 32 bit computer.

With a 64 bit operating system, larger amounts of RAM can be used to full advantage. In fact, the theoretical limit is 264, which is roughly equal to 16 exabytes. What's an exabyte? It's 16.8 million terabytes or 17.2 billion gigabytes - a huge number.

Both the 64 bit hardware and the 64 bit operating systems available today place a lower, artificial restriction on the amount of RAM that will be recognized. The 64 bit version of Vista Home Basic supports up to 8 GB, 64 bit XP Pro and Vista Home Premium both support 16 GB and Vista Business, Enterprise and Ultimate editions support 128 GB.

But even if your hardware supports 64 bits, you cannot take advantage of it or enjoy those higher RAM limits unless your operating system also supports 64 bits. Most computers sold today have 64 bit hardware, but many of them are running 32 bit operating systems. Windows XP Professional and all editions of Windows Vista except the Starter Edition (which is sold only in "emerging markets" outside the U.S.) come in both 32 and 64 bit versions. Vista Ultimate includes both versions in the box.

Just about everyone agrees that 64 bit architecture is the future of computing. On the server side, with some applications you have no choice. For example, the production version of Exchange Server 2007, the R2 of Office Communications Server (OCS) 2007 and Microsoft's Hyper-V virtualization platform are all 64 bit only.

It makes sense for server applications that require large amounts of memory. Hyper-V, for instance, needs to be able to allocate sufficient memory to multiple virtual machines, OCS has to process real-time audio and video streams, and Exchange is a memory-intensive application. Of course, some of us push the memory limits of our workstations, too. On my 32 bit Vista Ultimate computer with 4 GB, RAM usage typically stays in the 65% to 75% range if I have a few browser windows, Outlook, and Word open. In fact, RAM usage is over 50% when I first boot up, before I explicitly open any programs.

Vista is known to be memory-hungry, especially if you use its features to their fullest. If you're like me, you may also have lots of programs that load at startup and run in the background. For instance, I run Orb (for connecting to my computer remotely to access recorded TV and music through Media Center), MOE (the Mesh Operating Environment for connecting my various devices for easy synchronization), Groove Monitor (for using Microsoft's office collaboration system) and others at startup.

You can see what processes are using your memory by opening Task Manager (right click the task bar and select it, then click the Processes tab). Click the column labeled "Memory (Private Working Set)" to arrange the processes in order of their RAM usage. On my Vista workstation, Windows Sidebar is using 80,844 K (I do have a large number of gadgets). Vista Media Center, on which I'm watching a recorded program, is using 72,704 K, Outlook is using 35,716, the Desktop Window Manager (dwm.exe), which is responsible for the 3D effects, window transparencies and other graphical effects in Aero.

If you're using Internet Explorer 8 or Google Chrome, you might notice that you have several instances of those processes (iexplore.exe and chrome.exe), each taking up a chunk of memory. The way these browsers are able to provide better stability and prevent crashing the entire browser when one web site has a problem is by using tab isolation, which opens each tab in its own separate process. The tradeoff is that it takes more memory to run tabs separately.

Note that you can also view this same memory usage information, and a lot more, in Process Explorer. If you want to find out details about a particular process, just right click it and select Properties. You'll find far more info there than in Task Manager. In case you missed it in a recent issue of the newsletter, you can download Process Explorer at
Content not found all these processes using memory, you can see that the ability to use large amounts of RAM is a big advantage of a 64 bit system running a 64 bit OS. That being the case, why aren't we all running 64 bit Vista on our desktops? In a word, the answer to that one is "compatibility."

Although, as mentioned, some new applications run only on 64 bit machines, there are still many more 32 bit programs than 64 bit. Many of these can run on a 64 bit OS, through hardware compatibility mode or software emulation of the 32 bit environment, just as you can run old 16 bit DOS programs on 32 bit Windows. However, 32 bit applications don't take advantage of the larger address space so it's a little like buying a Lamborghini but only driving it on a residential road at 30 mph.

Native 64 bit apps are slowly seeping into the marketplace. Firefox, VMWare and Adobe's expensive imaging editing programs come in 64 bit versions. But Office 2007 and most other consumer and business productivity applications are still 32 bit programs.
The Knowledge Base (KB) Article You Requested Is Currently Not Available there are some 32 bit programs that won't work at all on 64 bit Windows. This includes most anti-virus programs. Some 32 bit programs need a patch to work properly on the 64 bit OS. Sometimes the problem is with the installer; there are some 32 bit applications that use 16 bit installers, and some 32 bit programs use 16 bit components. The catch is that 64 bit Vista does not support 16 bit programs or components.

The most common compatibility problem is with device drivers. Some hardware vendors still haven't come out with 32 bit Vista drivers for all their products, and 64 bit drivers can lag even further behind. Interestingly, though, you'll probably have an easier time finding drivers for 64 bit Vista than for 64 bit XP.

Ready to take a chance on 64 bit despite the possible compatibility issues? Be aware that you can't directly upgrade your 32 bit version of Windows to 64 bit Vista. You'll need to back up your data and settings (you can use the 32 bit version of Vista's Windows Easy Transfer to do this). You then have to start the installation from the 64 bit DVD. The installer won't run on 32 bit Windows. If you're currently running 64 bit XP, you can get an upgrade license to install 64 bit Vista, but you still have to do a clean installation. For more info on installation options under various scenarios, see KB article 932795 at
The Knowledge Base (KB) Article You Requested Is Currently Not Available the easiest way to get started with 64 bit technology is to buy a computer that comes with it preinstalled. You can find some real deals right now at the chain electronics stores on HP machines running 64 bit Vista Home Premium. On a recent trip to Best Buy, I noticed several machines with quad core processors and 4 to 6 GB of RAM for under $1000, all running 64 bit Vista with SP1. Check them out at
http://www.bestbuy.com/site/olspage....bcat0500000The advantage of buying a system with 64 bit Windows already installed is that you know there won't be driver issues - at least, not with the built in components. If you have a printer, web cam or other peripherals you need to use with the new computer, you might want to check the manufacturer's web site to find out if there are 64 bit drivers available.

Not quite ready to go all the way, but want to try running a 64 bit OS in a virtual machine? Not sure whether your hardware is 64 bit? Note that Microsoft's free Virtual PC software will run on a 64 bit host OS but does not support 64 bit guest operating systems. VMWare has a processor check tool that will help you determine whether you can run 64 bit guest operating systems in VMWare Workstation on it.
http://www.vmware.com/download/ws/dr...tools.htmlWhat are your experiences and opinions? Have you upgraded from the 32 bit world yet? Do you plan to do so anytime soon? What problems have you encountered? Are the advantages worth the challenges? Toss your 64 bits worth into the pot .