Windows XP Pro x64 Edition

A review

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Diagram representing the main editions of Windows XP. It is based on the category of the edition (grey) and codebase (black arrow).

Windows XP

Two different 64-bit editions were made available, one designed specifically for Itanium-based workstations, which was introduced in 2001 around the same time as the Home and Professional editions, but was discontinued a few years later when vendors of Itanium hardware stopped selling workstation-class machines due to low sales. The other, called Windows XP Professional x64 Edition, supports the x86-64 extension of the Intel IA-32 architecture. x86-64 is implemented by AMD as "AMD64", found in AMD's Opteron and Athlon 64 chips, and implemented by Intel as "Intel 64" (formerly known as IA-32e and EM64T), found in Intel's Pentium 4 and later chips.
winsupersite.com About the RC2 preview:
XP x64 is still a subset, of sorts, of XP 32-bit, but the missing features in XP x64 were dropped with good reason.

For example, XP x64 includes no 16-bit subsystem, so legacy MS-DOS and 16-bit Windows applications will not run on this system. Compatibility purists may look at that omission as a problem, but I agree with Microsoft's assessment that dropping 16-bit support is a chance to rid the system of messy legacy deadwood.
Also missing are legacy networking protocols such as NetBEUI and AppleTalk. Again, the chance to clean house, so to speak, should be applauded not condemned, even if it temporarily limits the size of the potential audience for this release. These are unnecessary technologies today, and Microsoft, understandably, doesn't want to support them forever.

In short, XP x64 looks and acts like the 32-bit version of XP Pro with Service Pack 2 (SP2). Virtually everything you see in a default XP Pro system is present in XP x64, including the Security Center, with just a few exceptions. There are also occasional features in XP x64 that aren't present in XP SP2, such as a 64-bit version of Internet Explorer. On the other hand, XP x64 also includes a 32-bit version of IE 6 for compatibility reasons: All the browser add-ons IE users take for granted will not work in IE x64. And as I'll discuss momentarily, compatibility issues are, in fact, almost the only major differentiator between XP x64 and XP Pro 32-bit.
In this preview of Windows XP Professional x64 Edition, I'll focus on the Release Candidate 2 (RC2) build of this product

My test system
In September 2004, I purchased a Hewlett-Packard (HP) Pavilion a640n desktop computer. This system shipped with an AMD Athlon 64 3400+ processor, 512 MB of RAM, a 160 GB hard drive, an NVIDIA-based Lancer FX5200XT video card (128 MB), integrated LAN and sound, two CD-type drives (DVD+RW and CD-ROM), and a nice 9-in-1 media reader.

I upgraded two components before making the a640n my main desktop over time. First, I replaced the lackluster Lancer video card with an ATI Radeon 9800 Pro (128 MB), which is more suitable for gaming. Then, I added another 512 MB of RAM to bump the system up to a full gigabyte of memory. I also upgraded the installed version of XP Home to XP Pro (32-bit). Through the end of 2004, I essentially multiple-booted the system between several versions of Windows, including XP Pro, two pre-release builds of Windows Server 2003 x64, and two pre-release builds of XP x64.

When Microsoft released Windows XP x64 RC1, I wiped out the system and dual-booted between XP Pro and XP x64.
Then, in February 2005, I wiped it out again, and I'm now running only XP x64 RC2 on the system, though I expect to eventually add an XP Pro partition for various compatibility reasons. My goal, however, is to live in a pure x64 environment for as long as possible to see if it's loable.

Compatibility
Back then, compatibility was a key issue for any Windows user considering NT. Specifically, you had two choices: The compatibility that came with Windows 9x, or the stability of Windows NT 4.0. Conversely, Windows 9x wasn't very stable at all. And Windows NT 4.0 wasn't very compatible with hardware or software. I recall printing out a portion of the NT 4.0 Hardware Compatibility List (HCL) every time I visited Best Buy, Fry's, or whatever, looking for a new network interface card (NIC) or other hardware component. Otherwise, you could find yourself out of luck. I wrote about the compatibility of Windows NT 5.0 Beta 2 in a showcase article way back in September 1998, and it's interesting to see how that experience is being mirrored today again with XP x64.
And now we have the x64 platform. Essentially an inelegant solution to a classic problem, x64 provides Windows users with a 64-bit environment that is backwards-compatible, for the most part, with the 32-bit software we run today. It also provides the full processing power of the underlying hardware, whether you're running 32-bit or 64-bit code, a feature the 64-bit Itanium sorely lacks. The problem, however, is that x64 is again splitting the Windows world, this time into 32-bit (x86) and 64-bit camps. On the 32-bit side, we have the full compatibility with all the hardware and software we've been using for years. On the 64-bit side, well ...

Not so good. Windows XP Professional x64 Edition is largely compatible with the 32-bit software we run today, though I've found glaring exceptions in the several months I've been testing pre-release versions of the system, including entire categories of hugely important software applications, like antivirus solutions. But XP x64 is not compatible with the multitudes of 32-bit hardware drivers that are currently available for every single device under the sun. So if XP x64 doesn't ship with a device driver for a particular piece of hardware you own, you have to pray that the manufacturer has created its own driver. As of this writing, very few have.

So. Once again, we have a split Windows market. On the left, we present the 32-bit versions of Windows XP, which offer the best hardware and software compatibility of any modern Windows operating system. And on the left, we have XP x64. This operating system is more stable and more secure than its 32-bit brothers, and can take advantage of significantly more hardware and software resources. However, it is not compatible with many of the software applications and applets, and hardware devices that you probably already own. This issue, more than anything, will determine whether XP x64 is a success or failure. Let's take a look at hardware and software compatibility separately.

Hardware compatibility
Hardware compatibility can be a killer, especially if you can't find a driver for a critical device, like a video card. Early builds of XP x64 didn't support the NVIDIA graphics card or the RelTek-based embedded sound card in my system, but I was able to locate beta versions of both. When I swapped in the ATI video card, however, XP x64 supported it automatically.
With the RC2 release, the audio card still wasn't supported, but RelTek was nice enough to post a brand new x64-compatible driver earlier this month, and that installed without a hitch. And as someone who still recalls the uneasiness of device support during the NT 4.0 days, I can state firmly that, with x64, there's just nothing like a clean Device Manager. So far so good.

However, when I begin adding other hardware devices, things don't go so well. My HP ScanJet 3970 scanner, for example, is not supported. My Canopus ADVC-50 analog-to-digital video converter is hopeless. And my Dell 1700n printer, which is network-attached, will not install using Dell's software, even though, oddly enough, it runs and completes Setup.

These are some of the types of devices people will need to work with using XP
x64. Since both HP and Dell are major Microsoft partners, and those devices are reasonably new, I expect them to eventually be supported.
But I wonder about the Canopus device. As of right now, I am trying to work around these issues. Since the Dell printer is really just a rebranded Lexmark printer, I installed drivers for the closest Lexmark model XP x64 supports natively, and they appear to work. And I can attach the scanner to one of my many other PCs. But most people don't have the home office set up I have. Those people would be left in the lurch by XP x64, or at least be forced to dual boot with XP 32-bit.

Other devices, like my iPods, work fine, which I guess makes sense since they're probably just seen as generic mass storage devices by the underlying system. The a640n's 9-in-1 media reader was automatically recognized exactly as it is in XP 32-bit, which is nice. I'll have more to say about hardware devices in my final review of this product.

Software compatibility
Software compatibility in XP x64, currently, is a disaster. Don't get me wrong:
Most 32-bit applications do indeed install and run on XP x64 just fine.
But I suspect that most people who try out this system over the next several months will be irritated to find that one of more crucial applications will not install at all, and that alone will give many a bad experience. Most of them, I suspect, will run right back to XP 32-bit.

I don't blame them. In my own admittedly unscientific testing, XP x64 simply wouldn't install some of the important applications that I rely on regularly. Inexplicably, most of them are Microsoft applications (Go figure). This should be profoundly embarrassing to the software giant, and hopefully someone at the company will ensure that all of its currently supported applications are patched to be x64 savvy by the time XP x64 is finalized. How can it expect third parties to work on x64 compatibility if Microsoft ignores it?

There are three main reasons for software incompatibility on x64, according to Microsoft. First, some applications are still using old-fashioned 16-bit installers, even though the applications themselves are 32-bit; since XP x64 doesn't support 16-bit applications, you can't install them on that system.
Second, many applications are poorly written to test for specific versions of the operating system, and since they see XP x64 as being newer, or different in some other way, to XP 32-bit, they simply refuse to install. I've tried XP x64's compatibility fix feature to try and get around this issue, but I've never been successful. Third, some applications actually let you install them, but then later check the OS version, so they don't run. These applications, presumably, could be "fixed" using the aforementioned application compatibility fix feature, but I haven't run into one yet to test.

When I install a new system, I run through a list of "always install" applications, which are highlighted in the table below. These are all of the applications I install first on every one of my system, because I use them regularly. As you can see from the list, XP x64's success rate was mixed. Most applications worked fine. But some of the ones that didn't are critical to me.

n addition to presenting this small subset of available x86 applications, I should note that XP x64 is incompatible with entire classes of applications, including antivirus applications and security suites (but not, curiously, antispyware solutions). Microsoft tells that these antivirus applications won't work in XP x64 because they access the system's kernel, which is 32-bit code in XP 32-bit but 64-bits in x64. However, all major AV vendors, including Symantec and McAfee, are allegedly working on x64-compatible upgrades. (Let's hope they don't charge existing customers for them.) In the meantime, it's hugely stupid to run any Windows version without antivirus protection.
I've only found one AV application--avast! antivirus 4.6 that comes in an x64 version. So I've installed the free Home Edition of this product in order to get some protection, but I'm not certain it's all that great yet. It's no Zone Alarm Suite, to be sure, but I presume it's better than nothing.

I also installed a large number of recently released video games, most of which worked just fine. Specifically, I installed Half-Life 2 (and the Steam application), Star Wars: Battlefront, Unreal Tournament 2004, Far Cry, DOOM 3, Painkiller, and Painkiller: Battle Out of Hell. All of these titles installed without a hitch, and most appear to run just fine.(I'm actually playing through the Painkiller expansion pack, Battle Out of Hell, for the first time now on the x64 system. It's been rock-solid.) DOOM 3 and Far Cry, however, wouldn't run initially. After I finally caved and installed ATI's beta video drivers, DOOM 3 started up without a hitch. But Far Cry refused to run. A day later, I mistakenly clicked on the Far Cry icon in the Start Menu while reaching for FrontPage. It ran, and ran fine. I have no idea why.

Aside from these peculiarities, the fear with games is that XP x64 won't perform as well as its 32-bit brethren. This hasn't been the case in my experience. After replacing a 2.8 GHz Pentium 4 Dell machine with the a640n running XP 32-bit, I noticed that the x64 hardware performed better in games (and was quieter to boot), despite the lower clock speed of the AMD chip in the a640n. Interestingly I used the same ATI video card in both setups, so the comparison is even more relevant. And when I moved the x64 system to XP x64, I didn't notice any drop in performance at all. The key here, naturally, is properly written video drivers. Today's hardware accelerated 3D games task the video card as much as they do the CPU, if not more.

I noted previously that the a640n originally shipped with an NVIDIA video card. Though NVIDIA should be lauded for regularly releasing beta versions of its x64-compatible video card drivers, I had problems with several revisions of them, resulting in slow screen refreshes and other graphical glitches. It's been a while since I've tested an NVIDIA card in this system, and I'm certainly not going to do so now, given the excellent results I've gotten with the ATI card. But NVIDIA gamers are advised to keep up on that company's x64 drivers. Some versions are better than others.

Some thougts about compatibility
For now, Microsoft can talk up the technical superiority of XP x64 all it wants, but compatibility issues are going to sink this operating system faster than you can say Microsoft Bob. There is little doubt that x64 is the future of desktop computing, but attempting to move to XP x64 will prove to be a fruitless trip for many people. To its credit, the software giant is being very clear about the near niche nature of its first x64-based desktop operating system, and the company has repeatedly told me that XP x64 is really just aimed at technical workstations, business desktop users, and enthusiasts.

Based on this information, and my own experience, I must issue a cautionary note to readers: If you're thinking about migrating to XP x64 immediately, don't. Instead, evaluate the RC2 version in a dual-boot scenario with XP 32-bit first. Test all of your important hardware and software and make sure they work, or at least work well enough. And do so knowing that, even if everything appears to work fine, it's possible that a desirable hardware device or software application will appear this year that simply won't work in XP x64.

These issues will diminish over time, of course. Hardware makers, hopefully, will surprise me and show up with vast reams of x64-compatible drivers and support the new system immediately. Sure, that's never happened before but you never know. Antivirus makers will suddenly vault into the x64 era with new XP x64 conversions of their popular and much-needed solutions. And all those 16-bit installers will slide silently into the sunset, never to bother us again. You never know.

In case it's not obvious, this version of XP will only run on x64-compatible hardware, that is, PCs with an AMD64 (Athlon 64 or Opteron) or Intel EM64T (Pentium 4 6XXX or Xeon)microprocessor.

Conclusions
Windows XP Professional x64 Edition Release Candidate 2 (RC2) is a rousing technological achievement, a near-perfect migration of Windows XP Professional to a 64-bit code base that doesn't sacrifice performance for 64-bit capabilities. But while XP x64 is far more compatible with hardware and software than its Itanium-based predecessor, it is also not compatible enough to meet the needs of average users. Therefore, most XP users should stick with XP 32-bit through at least the end of 2005.

If you're a technology enthusiast with the righthardware, however, XP x64 offers a chance to live on the edge in a way that hasn't been possible for Windows users since the HCL-wielding days of NT 4. With XP x64, Microsoft has provided a superb technological base for the next several years, one that will likely become the mainstream computing platform during the Longhorn time frame. Like a faraway land full of treasure real or imagined in an age of explorers, XP x64 is there for the brave and foolhardy. Are you up to the challenge? ---Paul Thurrott February 21, 2005

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AMD64 and Intel Extended Memory 64 Technology

Conclusion
Well, CPUs supporting 64-bit extensions of the x86 architecture are currently available from both major CPU manufacturers. And they are going to be shipping in even bigger quantities in the nearest future. In other words, the first step towards mass transition to 64-bit applications has already been made.
The second step in that direction will follow shortly. It will be the release of the 64-bit user operating systems, with Windows XP Professional x64 Edition being among the most important ones. After that 64-bit software and applications will start overwhelming the market. So, it looks like we will be witnessing a massive transition from the obsolete 32-bit architecture to the more advanced 64-bit one.

In fact, we haven’t yet fully faced the limitations imposed by the 32-bit mode, and the 4GB of RAM seem quite enough for any type of tasks.
However, progress keeps going and very soon we will see that much RAM only by the entry-level systems. This is exactly when we are going to see true advantages of the 64-bit processors and operating systems.

However, we have to state that the entire infrastructure necessary for successful transition to 64-bit era is almost ready. The operating system ready to be released works just fine, even though it is still an RC1 revision. Most drivers have also been almost finalized by now. All we can do now is wait until Windows XP Professional x64 Edition comes out, which should happen in H1 2005.

A really big advantage of the new Windows XP Professional x64 Edition OS is its ability to allow smooth transition from 32-bit applications to 64-bit ones, because it supports both: usual 32-bit software and the new 64-bit programs.
Moreover, our today’s test session showed that 32-bit programs are performed in Windows XP Professional x64 Edition without any significant performance losses. This way, if you are a happy owner of a CPU with AMD64 or EM64T support, you have green light to install Windows XP Professional x64 Edition. Just keep in mind that it still might be incompatible with some specific software and hardware, so you’d better double-check first.

As for the performance quality provided by the CPUs from AMD and Intel when processing 64-bit extensions, it is still too early to make any final verdicts about that. According to our preliminary testing in a very limited number of benchmarks, CPUs supporting AMD64 technology provide higher performance gain when working with 64-bit code than the CPUs supporting EM64T.
However, the opposite is also true once there is proper optimization for the EM64T technology, and in this case we saw Intel processors show much better potential than the competitor’s solutions.

Advantages

The primary benefit of moving to 64-bit is the increase in the maximum allocable system memory (RAM). A single process on a 32-bit Windows operating system is limited to a total of 4 GB,
which is typically equally divided between kernel and application
usage. Windows XP x64 can support much more memory; although the
theoretical memory limit a 64-bit computer can address is about 16 exabytes, Windows XP x64 is limited to 128 GB of physical memory and 16 terabytes of virtual memory.

64-bit processors calculate particular tasks (such as factorials of
large figures) two times faster than working in 32-bit environments
(given example is derived from comparison between 32-bit and 64-bit
Calculator, noticeable for factorial of say 100 000). This gives a
general feeling of theoretical possibilities of 64-bit optimized
applications.
Windows XP Professional x64 Edition and Windows XP 64-bit Edition Version 2003 are the only releases of Windows XP to include Internet Information Services 6.0, which matches the version shipped with Windows Server 2003; other versions of XP include 5.1.

64-bit versions of Windows XP are also immune to certain types of
32-bit viruses such as root kits, as most system files are 64-bit.
Spyware and other malware may still run on both 32-bit and 64-bit.
The extra registers of the x86-64 architecture can result in performance improvements in certain kinds of applications.