Windows XP 64-Bit Edition for 64-Bit Extended Systems Preview

One of the major topics attracting the public attention when they touch upon AMD Athlon 64 FX and Athlon 64 processors is the discussion of their 64bit capabilities. Unfortunately, there is not much to talk about yet. There are no public operation systems supporting 64bit AMD64 extensions that is why the biggest part of our today?s article will be devoted to the performance of Athlon 64 FX-53 in 32bit Windows XP operation system.

However, the situation is not as hopeless as it might seem at first glance. AMD has already sold quite a bit of processors supporting AMD64 technology. Moreover, Intel has also announced their long-term intention to introduce AMD64-compatible 64bit extensions support in its upcoming desktop CPUs in the far-away future. That is why it is more than evident that AMD64 technology will become a success one day. Sooner or later 64bit operation systems and the whole lot of 64bit software will come to the market. Especially, since software developers have no alternatives left: if the program will require more than 2GB of memory then the only way to solve the problem is to use 64bit processor mode.

But this is the future. Although there is some movement towards the use of AMD64 technology today already. The first remarkable event in this field took place in the beginning of February, when Microsoft Company offered everyone the opportunity to get acquainted with a preliminary version of their Windows XP operation system with AMD64 technology support. This OS is officially called Windows XP 64-Bit Edition for 64-Bit Extended Systems and is available for free download on the Microsoft web-site. Of course, we couldn?t leave out this fact and took a closer look at the new operation system.

I would like to stress that this is the second time already we get to work with a Windows version supporting AMD64 technologies. In our article devoted to AMD Athlon 64 FX-51 we have already provided some benchmarks results obtained in this OS. However, at that time we had an earlier beta-version of Windows XP 64-Bit Edition for 64-Bit Extended Systems at our disposal. Although at that time already it worked flawlessly, without any evident bugs. The public demo version of this OS is marked with a newer date and works without any problems on Athlon 64 FX/Athlon 64 processors. However, this system is hardly suitable for every-day use. In fact, it can be useful only for software developers and testers who simply have to use a 64bit system. Regular users do not need to shift to Windows XP 64-Bit Edition for 64-Bit Extended Systems and sometimes simply cannot do it at all.

The first problem you face when installing Windows XP 64-Bit Edition for 64-Bit Extended Systems is the lack of necessary drivers. Very few hardware developers offer drivers for their devices, which are compatible with the Windows versions supporting AMD64. Regular 32bit drivers cannot be used for 64bit operation system. For this reason, for instance, the owners of Windows XP 64-Bit Edition for 64-Bit Extended Systems cannot use ATI based graphics cards in their systems: the Canadian company doesn?t supply the graphics card drivers for this operation system yet. Also the owners of some network cards, RAID controllers and audio solutions may face similar problems. That is why if you decide to install Windows XP 64-Bit Edition for 64-Bit Extended Systems in your PC, make sure that you?ve got drivers for all the hardware devices you have in your system.

The second problem is the lack of appropriate software. Although, one of the strengths of AMD64 architecture is its backward compatibility with 32bit software. Therefore, this is no fatal problem at all. Most 32bit tools and utilities work fine with Windows XP 64-Bit Edition for 64-Bit Extended Systems due to the so-called WOW64 (Windows-on-Windows) emulator, which transfers the CPU from the native 64bit mode into the compatibility mode, so that the application can manipulate the CPU registers and address the memory in 32bit format. During the tests we carried out for various 32bit programs we revealed just a few issues. The first one had to do with the failing installation of Windows Media Encoder 9 with all the resulting consequences, while all other issues were connected with different artifacts popping up in 3D games every now and then. Of course, it was the graphics card driver that was responsible for the latter problems.

At the same time, the variety of software developed specifically for 64bit mode of AMD64 processors will keep increasing. Some programs are already available today, although there are very few of them, I should say. In particular, we know about 64bit versions of TweakUI Power Toys utility, Sun Java 2 platform and beta version of Computer Associates eTrust Antivirus.

Windows XP 64-Bit Edition for 64-Bit Extended Systems operation system looks very much like Windows 2003 and not like Windows XP. It looks as if they used exactly the Windows 2003 code when they were working on the Windows XP version with AMD64 support. The OS includes a set of 64bit DirectX 9.0b libraries and a set of standard programs ported for AMD64 architecture. It is a pretty curious fact that Windows XP 64-Bit Edition for 64-Bit Extended Systems includes not only a 64bit version of Internet Explorer 6.0, but also a classical 32bit version of this program. Also the 64bit Windows XP package will include a number of critical updates absent in the standard Windows XP SP1 package for 32bit systems.

I would also like to say a few words about the test system, which we used for Windows XP 64-Bit Edition for 64-Bit Extended Systems testing. The thing is that the standard platform configuration didn?t suit our goals this time, as we failed to find corresponding drivers for a few components of our system. That is why we had to replace an ATI based graphics card with an NVIDIA based one. As a result, Athlon 64 FX-53 was tested on the following system:

CPU: AMD Athlon 64 FX-53;
Mainboard: ASUS SK8V (VIA K8T800);
Memory: 1024MB Registered DDR400 SDRAM (Mushkin High Performance ECC Registered 2 x 512MB, 2-3-2-6);
Graphics card: Sparkle GeForce FX5900XT (Detonator 53.04).
HDD: Western Digital WD400JB.
In order to finish our story about the preliminary version of Windows XP 64-Bit Edition for 64-Bit Extended Systems in a logical manner, we decided to test AMD Athlon 64 FX-53 processor in this operation system during the processing of 32bit and 64bit applications.

At first I would like to say a few words about the 64bit performance. Unfortunately, our opportunities were pretty limited because there were hardly any applications compiled for native 64bit mode. The only available benchmark for Win64 is a 64bit version of SiSoft Sandra 2004 SP1. This test package includes short synthetic benchmarks for the CPU and system memory. Due to these tests we get at least some idea of the system performance in Windows XP 64-Bit Edition for 64-Bit Extended Systems. At the same time I would like to say that SiSoft Sandra 2004 SP1 also exists for Win32. So, we get an excellent opportunity to compare the results of this test during 64bit code processing in 64-bit Windows XP with those during 32bit code processing in 64-bit and 32-bit Windows XP versions.


The results are pretty ambiguous. In some tests the shift to 64bit mode leads to a notable performance gain, while in some cases the performance drops significantly. However, first of all I would like to say that 32bit benchmarks from the Sandra package were run equally fast in 32bit and 64bit operation system. This way, I can conclude that WOW64 emulation doesn?t cause any delays of the 32bit code processing.

Returning to the results in 64bit SiSoft Sandra 2004 in Win64 I would like to point out that the shift to 64bit mode allows AMD64 processors to speed up the work with the system memory quite tangibly. However, this is almost the only case (besides Whetstone FPU benchmark) when 64bit technology has a positive effect on the performance, according to SiSoft Sandra 2004. In all other cases the performance in 64bit mode is either the same or lower. Unfortunately, we can?t state with all certainty why the 64bit performance is considerably lower than 32bit performance in Multimedia Integer MMX/SSE and Whetstone SSE2 benchmarks. The most probable explanation here is the poor optimization of the test algorithms for AMD64 technology. All exiting compilers generating the code for Windows XP 64-Bit Edition for 64-Bit Extended Systems are only available as alpha- or beta-versions, that is why no one can guarantee their efficient work today.

At the same time, if the code of the 64bit SiSoft Sandra version is not very well optimized for AMD64 architecture (for instance, it uses nearly none of the additional general purpose registers), we can also face a noticeable performance drop but for a different reason. In 64-bit mode Athlon 64 processors perform certain instructions (namely integer multiplication and division) somewhat slower than in 32-bit mode. However, this explanation suits only for Dhrystone ALU benchmark, because Athlon 64 performs all SSE2 instructions equally fast in 32-bit and 64-bit modes.

Unfortunately, besides SiSoft Sandra 2004, there are no other applications at our disposal today supporting 64-bit mode and offering some benchmarking opportunities. That is why let?s pass over to a more indepth investigation of the 32bit applications performance in Windows XP 64-Bit Edition for 64-Bit Extended Systems.

Since we are now talking only about a preliminary version of this OS, it doesn?t make much sense to carry out very detailed test session with the whole bunch of applications involved. For our preview we will simply run PCMark 2004 test, which measures the performance of the most widely spread algorithms.


As we see, typical 32bit procedures loading the CPU and the memory show almost the same performance level in 64bit Windows version as they do in 32bit Windows. In other words, this is another proof to the fact that the use of WOW64 emulator doesn?t cause any performance drop in 32bit applications running under 64bit operation system. However, according to the obtained results there are two exceptions to this rule.

The first exception. Web Page Rendering test shows a much higher result working in 64-bit Windows version. This happens because the test measures web-pages rendering speed with the help of the Internet Explorer version installed in the system, and of course, in Windows XP 64-Bit Edition for 64-Bit Extended Systems this is a 64-bit version too. This way, we can clearly see that 64-bit Internet Explorer is tangibly faster than 32bit one, and Athlon 64 processors really do ?speed up? web-surfing.

The second exception. It has to do with the last two benchmarks, which indicate a performance drop during their work in 64-bit operation system. Moreover, this performance drop is not so crucial in the 3D benchmark, while in 2D benchmark (the very last one) it is simply dramatic. In this case I would blame the graphics driver for such a failure of the 64-bit system. It looks as if the situation with the drivers for Windows XP 64-Bit Edition for 64-Bit Extended Systems is aggravated not only by the absence of these drivers. As we have just seen, the existing drivers are far from ideal as well. The best example here is Detonator from NVIDIA. However, we should be fair: ATI has no drivers at all, which would support processors with AMD64 technology in 64-bit operation systems.

To prove everything I have just said, here are the results of 32-bit games tests in Windows XP 64-Bit Edition for 64-Bit Extended Systems:


The numbers speak for themselves, I suppose. 32bit games run under Windows XP 64-Bit Edition for 64-Bit Extended Systems work much slower than in the regular Windows XP Professional. Moreover, there are some problems with the actual work of the gaming applications. We discovered very bad artifacts in a number of our test 3D applications, such as Aquamark3 or X2 ? The Threat. All in all, NVIDIA still has a lot to do about the improvement of its 64-bit graphics drivers.

Summing up everything mentioned above, the verdict about Windows XP 64-Bit Edition for 64-Bit Extended Systems will not be praising. So far this system may be of interest only to the developers. Regular users will not be happy with it because of the availability matters as well as the drivers quality. However, it is very nice that the process of developing applications supporting AMD64 architecture has finally taken off. The official launch of Windows XP 64-Bit Edition for 64-Bit Extended Systems is scheduled for H2 2004, so hopefully the hardware guys will be able to eliminate the problems with their drivers by then, and the software developers will successfully port their programs for 64-bit operation system and 64-bit working mode.

Thanks to X-bit Labs for the full article