Windows XP Professional x64 Edition RC1 tested

Release Candidate 1 (RC1) of Windows XP Professional x64 Edition is now available: ZDNet has put Build 1289 through its paces.
Written by Kai Schmerer, Contributor

Just before Christmas, Microsoft finally made Release Candidate 1 of Windows XP Professional x64 Edition available to testers. The server variant is also now available. After repeated delays, Windows XP Professional x64 Edition is now due to ship in the first half of 2005.

If previous experience with Microsoft operating system releases is replicated, Build 1289/RC1 will be followed by a further release candidate (RC2) and then the marketable ('gold') version. If no further problems emerge, Windows XP Professional x86 Edition could reach gold status by the time of the CeBIT show in March.

The route into the 64-bit world was accelerated thanks to AMD's AMD64 technology, which is used in the Athlon 64 and Athlon 64 FX desktop processors and in the Opteron server chip. In contrast to Intel's Itanium, AMD's 64-bit architecture can handle 32-bit code very fast, which makes for a smooth transition to 64-bit computing.

Intel has been non-committal about this state of affairs, the official line for a long time being that "nobody needs 64 bits on the desktop right now". This then became the promise that: "as soon as an x86 64-bit Windows operating system is available, we will support it". The open source Linux operating system has been available for some time for AMD's x86-64 platform. However, 64-bit computing will only take off in the business market once 64-bit Windows is available, since most business users currently work with the Microsoft operating system.

Windows XP Professional x64 Edition, Build 1289 Release Candidate 1.

Not all applications are available in a 64-bit version, including Internet Explorer. Missing 64-bit plug-ins such as Shockwave, Flash and Java VM mean that the 64-bit version of Internet Explorer cannot render numerous Web sites. There are no problems with the 32-bit version in this respect.

Windows Update currently works only with the 32-bit version of Internet Explorer.

Installation and driver support

Release Candidate 1 of Windows XP Professional x64 Edition installed without problems on our test system, taking approximately half an hour. Fortunately the new Windows -- in contrast to the 32-bit version -- supports a lot of newer hardware without the need for special drivers to be installed.

The test system comprises an Asus A8N-SLI Deluxe Nforce4 motherboard, an Nvidia GeForce 6800GT PCI Express graphics card, a Seagate EIDE hard disk and a Matshita DVD-ROM. The motherboard hosts dual Gigabit LAN controllers from Nvidia and Marvell, and an appropriate driver must be installed for the Nvidia chip. Although 32-bit applications run without problems under 64-bit Windows, appropriate 64-bit device drivers must be present. You cannot install 32-bit drivers under Windows XP Professional x64 Edition.

Fortunately, 64-bit drivers already exist for the most important hardware components -- AMD's Web site lists the current 64-bit drivers for the Windows and Linux platforms. However, it may take several years for the level of driver support to reach that of 32-bit Windows today. Naturally, drivers are more likely to be available for newer and more popular hardware: whether older devices will ever be supported under 64-bit Windows remains to be seen.
Antivirus software, browser plug-ins, games, 16-bit programs
Because of missing 64-bit support, active virus protection for email is currently only available with Avast Antivirus 4.5 and McAfee Enterprise 8.0i. All other virus protection programs offer only a manual virus scan of your data at the moment -- incoming email is not examined. The other antivirus software vendors are expected to have their 64-bit versions ready when Windows XP Professional x64 Edition ships.

As far as browser plug-ins are concerned, 64-bit versions of Flash, Shockwave and Java VM should be present when Windows XP Professional x64 Edition ships. The Microsoft .Net Framework is already available in beta as a 64-bit version. If other plug-ins are missing, it's not the end of the world: Release Candidate 1 comes with a 32-bit version of Internet Explorer, which works with current 32-bit plug-ins without problems. The same goes for the recently released Firefox browser. As a result, switching to the 64-bit version of Windows should not cause any degradation of your Internet experience.

The situation is different with games -- particularly newer ones with copy protection systems. For example, we could not start DTM Race Driver 2 because the driver for the copy protection (Starforce) is present only as a 32-bit version.

16-bit programs do not run
Anyone who still uses older 16-bit programs can forget about running them under 64-bit Windows. However, some 32-bit applications use 16-bit code during installation, which means that these programs cannot be installed. This might cause some nasty surprises. For example, the Ziff-Davis Business and Content Creation Winstone benchmarks cannot be installed under 64-bit Windows because of their 16-bit install routines.


With a new operating system, performance is decisive for many users. However, since there are no 64-bit applications available for the Windows platform at the moment, the focus is largely on 32-bit performance.

We did ask some manufacturers for 64-bit Windows software. The 64-bit versions of Unreal Tournament and Shadow Ops should be available shortly, and 64-bit applications such as Panorama Factory are in the pipeline. As soon as 64-bit programs become available, we will evaluate their performance compared to their 32-bit counterparts.

The 64-bit version of Windows can more address more memory. With the 32-bit version the maximum is 4GB, while systems running the 64-bit version will have as much as 32GB. For desktop PCs there may be little immediate advantage, as few users are likely to be troubled by the current 4GB limit. However, a closer examination of the memory subsystem reveals some disadvantages of 32-bit Windows. For example, the maximum size of the non-paged pool of memory is only 256MB, compared to 128GB under 64-bit Windows. The operating system uses this pool for virtual addresses, which remain in memory and are not paged out to the hard disk. The bigger this pool, the faster the operating system.

Differences between 64-bit and 32-bit Windows

Address space
Windows 64
Windows 32

Virtual memory 16TB 4GB
Paging file 512TB 16TB
Paged pool 128GB 470MB
Non-paged pool 128GB 256MB
System cache 1TB 1GB

Compared to a 32-bit operating system, a 64-bit OS needs more memory. The comparison table below shows that kernel of the 64-bit version takes up nearly 70 per cent more memory than its 32-bit counterpart. So in order to get the same performance level, users switching to 64-bit Windows will need to upgrade their systems' memory.

Storage requirements: 64-bit v 32-bit

Kernel memory (KB)
Windows XP 64
Windows XP 32

Total 52120 31344
Paged 40572 25396
Non-paged 11548 5840


Driver performance

The GeForce drivers contained in Release Candidate 1 have the version number 66.96. The drivers offered by chip manufacturer Nvidia have the same identification. Nevertheless there are both functional and performance differences between the two sets of drivers.

The Microsoft drivers cannot implement OpenGL code. An application that accesses this graphics interface is stopped by the system. We therefore recommend that you install the manufacturer's drivers. In any case, Nvidia's drivers deliver better performance, as the comparison below using 3D games shows. The Microsoft drivers only beat their Nvidia counterparts in the 3DMark 2005 test with anti-aliasing and anisotropic filtering turned off.

Driver performance

Operating system
Windows XP 64

Resolution / colour depth 1024 x 768 / 32-bit

3DMark 2005 (MS 66.96) (score) 4585
3DMark 2005 (Nvidia 66.96) (score) 4493
3DMark 2005 (MS 66.96) 4xAA, 8xAF (score) 3740
3DMark 2005 (Nvidia 66.96) 4xAA, 8xAF (score) 3793
UT2004 Albatross (MS 66.96) (fps) 70.8
UT2004 Albatross (Nvidia 66.96) (fps) 71.0
UT2004 Desert Isle (MS 66.96) (fps) 100.8
UT2004 Desert Isle (Nvidia 66.96) (fps) 101.6

3D games performance

Broadly speaking, 64-bit Windows can run 32-bit games as fast as 32-bit Windows does. In terms of stability, there are even advantages in using the 64-bit version: Windows XP Professional x64 Edition did not crash at all during our tests, whereas the current XP version needed a reboot during the Unreal Tournament Albatross test.

However, this is possibly due to the different drivers for the GeForce card. Nvidia offers version 66.96 for 64-bit Windows, but 32-bit Windows is still officially at version 66.93 (although version 71 is circulating on the Internet). Obviously it would be preferable to use the same driver versions, in order to eliminate this factor from the comparison between 64-bit and 32-bit Windows.

3D performance

Operating system
XP 64 (66.96)
XP 32 (66.93)
XP 64 (66.96)
XP 32 (66.93)
XP 64 (66.96)
XP 32 (66.93)

Resolution 1024 1024 1280 1280 1600 1600

3DMark 2005 (score) 4585 4830 3792 3942 3195 3305
3DMark 2005 4xAA, 8xAF (score) 3740 3859 3030 3074 2263 2319
UT 2004 Albatross (fps) 71.0 72.7 70.7 72.4 70.5 72.2
UT 2004 Desert Isle (fps) 101.6 104.2 99.3 102.2 91.6 94.2
UT 2004 Albatross 4xAA, 8xAF (fps) 70.8 crashed 69.6 crashed 57.9 crashed
UT 2004 Desert Isle 4xAA, 8xAF (fps) 95.3 98.1 77.3 79.4 58.8 60.1
UT 2004 Albatross 4xAA, 8xAF HQ (fps) 65.1 65.5 51.4 51.7 38.6 39.3
UT 2004 Desert Isle 4xAA, 8xAF HQ (fps) 79.3 79.5 58.1 58.5 44.5 44.8
Doom 3 4xAA, 8xAF HQ (fps) 70.1 62.5 49.9 46.7 37.7 36.2
Doom 3 4xAA, 8xAF (fps) 75.1 75.2 53.3 53.5 39.6 40.1
Doom 3 (fps) 103.4 108.4 86.6 89.4 69.9 71.2

Build 1289 of 64-bit Windows XP already appears to be relatively well developed. Certainly it showed no evidence of instability during our tests. And as far as performance is concerned, we can expect the 64-bit version to match the current version when running 32-bit applications.

When it comes to support for newer hardware, Windows XP Professional x64 Edition offers some advantages over the 32-bit version. For example, the Nforce4 chipset is supported as standard, which is not the case with the current version of Windows XP. Support for older hardware looks more problematic, although manufacturers still have several months to get driver support in place for their products.

Although driver support may not be a huge problem, that's not the case with 64-bit applications. Switching to a 64-bit operating system only makes sense if applications are available that either run faster or offer more functions than their 32-bit counterparts. The changeover from 16-bit to 32-bit computing lasted some time, until the newer platform offered clear advantages. This same will undoubtedly happen with the 32-bit-to-64-bit transition.

The availability of Windows XP Professional x64 Edition is a first step toward 64-bit computing on the desktop, but further ones must follow. Doom3, FarCry and other top games will soon be available for the 64-bit platform, and if performance advantages are evident with the arrival of these games, home users could give the 64-bit platform a boost. Then perhaps Intel will finally jump up on the 64-bit-bandwagon that was set rolling by AMD and Microsoft.

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