Update on the Windows Experience Index

by Greg Shultz | Mar 07, 2007 8:00:00 AM

Tags: Operating systems, Microsoft Windows Vista (Longhorn), Greg Shultz, Microsoft Windows, Windows Experience Index, Windows eXPerience, Microsoft Windows Vista, graphics

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Takeaway: Now that Windows Vista has been officially on the street for a little over a month, lots of folks have been talking about the Windows Experience Index, sharing information on their scores, and asking plenty of questions. Here we revisit the topic and provide more current information.

As you probably know, throughout the Windows Vista Beta and Release Candidate cycles, I've written several articles about Windows Vista's hardware requirements and the Windows Experience Index. (In the earlier stages of Vista's development it used to be called the Windows System Performance Rating.) Well, now that Windows Vista has been officially on the street for a little over a month, lots of folks have been talking about the Windows Experience Index, sharing information on their scores, and asking plenty of questions. I thought that I would revisit the topic and provide more current information about the Windows Experience Index.

An overview of the Windows Experience Index

To get a handle on exactly what the Windows Experience Index means and how it works, you must first understand that Windows Vista is a scalable operating system. When you install Windows Vista on a specific computer, the installation procedure runs a tool that analyzes several key hardware components in your system and then essentially customizes certain features in order for them to perform optimally on your system based on the capabilities of your hardware.

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This analysis and scalability is performed by the Windows System Assessment Tools or WinSAT for short. During the analysis, WinSAT assigns a number from 1 to 5.9 to each of the key hardware components, calculates an overall base score, and then scales the operating system's features to fit that score. This base score, and the scores assigned to each of the key components, make up the Windows Experience Index.

The ultimate goal of the Windows Experience Index is to make it easy to match software with the capabilities of a computer running Windows Vista. For example, a system with a Windows Experience Index base score of 3.0 will be able to optimally run any software that carries a Windows Experience Index rating of 3.0 and below. On the other hand, a system with a Windows Experience Index base score of 2.0 won�t be able to satisfactorily run any software that carries a Windows Experience Index rating above 2.0.

The key hardware components

The key hardware components that WinSAT measures and rates during its analysis are the processor, the memory, the graphics card, and the hard disk. While the processor, memory, and hard disk are assigned one sub-score, the graphics card is actually assigned two sub-scores.

The Processor sub-score measures the performance of the processor when tasked with several common Windows usage activities including compression and decompression of files, encryption and decryption, and video encoding, just to mention a few. The Memory sub-score is based on the amount of available physical memory in the system as well as the speed with which the actual chips move data in and out of memory.

The first of the two graphics card scores, the Graphics sub-score, indicates how well a computer will run Windows Aero and play back Windows Media video. This measurement is based on the amount and bandwidth of dedicated video memory, as well as DirectX 9 support and the capability of the card�s WDDM Driver (Windows Vista Display Driver Model).

The second of the graphics card scores, the Gaming Graphics sub-score, is based on the frames per second at which the graphics card can handle different textures. Other factors that contribute to this sub-score include Direct 3D 9 support and Pixel Shader 3.0 support.

The Primary Hard Disk sub-score measures disk bandwidth in megabytes per second. Advances in hard disk technology have made this sub-score pretty standard as most modern hard disks will typically score above 3.

The numbers

As I mentioned, the scale of the Windows Experience Index ranges from 1 to 5.9 and of course, the higher the score for a particular component, the better performance you can expect from that component. (Scores of 6.0 and higher are not defined yet in order to leave room for advancements in technology.)

Each component will receive sub-score and the system itself is assigned an overall base score. However, rather than being an average, the base score is essentially taken from the lowest of the five sub-scores. The reasoning here is that the slowest or least-powerful hardware component will effectively hold the system back and therefore must be the defining factor for overall performance base score. In other words, you're only as strong as your weakest link.

An example

Let's take a look at the Windows Experience Index score for one of my test systems. This particular system includes a AMD Athlon 64 X2 (dual-core) 4800+ processor running at 2.41 GHz, 2 GB of RAM, a 256 MB NVIDIA GeForce 7300 LE, and a 160 GB Seagate Barracuda SATA hard drive.

As I was constructing this particular system, I was thinking that it would easily garner a Windows Experience Index score at or near the top of the scale. And, as you can see by the sub-scores assigned to the processor, RAM, and hard disk, this is definitely an achievable goal. However, as you can see in Figure A, the Graphics sub-score, at 2.7, brought the base score way down.

Figure A

As you can see, the base score of this hefty system was brought down due to the sub-score of the graphics card.

Since the card by itself is advertised as being built for Windows Vista and has all the necessary attributes to achieve a higher scor, i.e., ample RAM, DirectX 9 support, Pixel Shader 3 support, and WDDM driver support, I was confused and disappointed.

Since the card was using a Microsoft WDDM driver I immediately went to the NVIDIA site and downloaded and installed the most current driver. Unfortunately, the Graphics sub-score didn�t change.

Upon returning to the NVIDIA site I discovered a disclaimer stating that the NVIDA Windows Vista drivers for this card are still under development and that this version is not fully optimized for full 3D performance and may not include all available features available on different operating systems. So I�ll keep checking for more solid drivers.

Share your score

While researching this topic I came across the ShareYourScore site where you can submit your Windows Experience Index score. To share your score, you follow the online instructions for uploading the WinSAT XML file on your system.

The really interesting feature of this site is that you can access the Component Details section, select any of the available graphics cards, and see their scores as well as get detailed information on the card. You can also access the Component Scores section and view the score rankings for the top CPUs and graphics cards.

Now that Windows Vista has been available for a while, the Windows Experience Index is beginning to attract a lot of attention. If you have any information or comments to share about Windows Vista�s Windows Experience Index, please stop by the Discussion area and let us hear from you.

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