In another effort to stem the influx of repeated 64bit related threads, I have compiled a FAQ from the questions asked in here. Please feel free to comment on the content, or suggest additions. We also have a thread in the archive here, which has some great links for downloads/drivers related to x64. What is it? The x64 editions of Windows XP and Windows Server 2003 are versions of the operating system that support x64 extensions to the x86 architecture. The "64-bit" designation refers to many aspects of the architecture: the width of the general purpose registers; the widest integer and logical operations supported by the processor; the size of values pushed and popped from the stack; and the width of the pointer data type, or virtual addresses. Do I need it? If you have to ask this question, then the answer is probably no. Specific applications that can benefit from the 64bit extensions provide a stronger appeal for those that use them. If you rely on virtualisation software, or program compilers for instance, there are applications out there which will directly benefit from a native 64bit environment - and in theory run faster. This isn't to say that, if you dont use any of these applications, you couldn't see any benefit from the x64 editions, if you have a suitable setup. Systems with 2gb of memory plus, or SMP (multi-processor/core) systems for instance could see a noticeable benefit by running x64 - however it isn't a black and white decision. The first hurdle you need to overcome is finding drivers for all your hardware, which might not be as easy as you'd hope. Drivers for x64 are gaining in number as the weeks go by, so check out the links in our archived x64 thread to see if you can turn one up. The other thing to consider, is that compared to the 32bit versions of Windows, x64 is very much a product in its infancy, and there is a significantly smaller amount of information available on the internet, possibly making it harder to find support if you need it. This is much more of a concern with third party applications, rather than the OS itself. If you're running some 32bit software on x64 and stumble across a bug - it's unlikely you'll get support from the developers if they dont officially support the platform. Many people (myself included) report very few, if any problems when it comes to 32bit emulation, but it's still a chance you take. What does it require? A 64bit processor from AMD or Intel - These are the Athlon 64 processors from AMD, and the EM64T processors from Intel. You'll also want hardware from vendors that support the 64bit architecture. Can I just upgrade to x64? Unfortunately not, moving to x64 requires a fresh install. The same is true of the reverse (reverting to 32bit Windows from x64). Can I dual boot? You certainly can, many people go down this route first while they try all their drivers and software. General multi-boot information can be found in the sticky. Can I run my old, 32bit programs? x64 does indeed support 32bit software emulation, and it's very good. Rarely do people report problems running their 'old' software, and the few problems that are reported can often be solved with a quick update. There are, of course, occasional exceptions to this. It's rare, but some bits of software (often small freeware apps), or features within them, simply wont work. A good compatability guide can be found over at 3dvelocity here. Processes running in 32bit emulation mode are highlighted in task manager by '*32' at the end of the process name. What firewall/antivirus can I run on x64? Both products come with Windows Firewall as standard, and it works very well, but if you need outbound program control (something which wont be apart of Windows Firewall until Vista), then you need to look at one of the following alternatives. Credit to Xee for the info: As for antivirus, a credible free option available is Avast! - a personal favourite of mine. If you dont mind paying a little money, then NOD32 is sited on this here forum as one of the best packages available. I believe the x64 support is still in beta, however. I cant find a driver for 'x' device, what do I do now? Not a lot unfortunately. 64bit drivers are absolutely required running x64, and if there are none available for your hardware device, then it just cant be used. Email the manufacturer and ask the question, and check around the links in our archived threads for news from them. Sources Wikipedia Microsoft.com These hyah forums Me.