Interpreting the Windows Experience Index

How important is the WEI base score (the lowest of the subsystem scores) to your satisfaction with Windows 7? According to Microsoft, computers with base scores of 2 or less will satisfactorily perform basic tasks such as office productivity or web surfing but are probably not powerful enough to run Windows Aero or advanced multimedia features. Computers with a base score of 3 can run Windows Aero but may not be powerful enough to run high-end features such as Aero across multiple displays or display HDTV. Computers with a base score of 4 or higher can use all features. Systems with higher scores will perform better in 3D gaming. The highest score, 7.9, was achieved by the fastest-performing computers available when Windows 7 was released. If you previously used Windows Vista, you might recall that the highest WEI score was 5.9. By increasing the maximum score to 7.9, Microsoft provides more headroom for today’s faster subsystems. Microsoft’s Engineering Windows 7 blog points out changes in WEI ratings of hard disks and graphics:

• Hard disks with poor write cache flush performance will receive lower disk scores compared to the same hardware measured under Windows Vista’s WEI. Most conventional hard disks with properly operating write flush cache are expected to score in the 5.0–5.9 range. Extending the scoring range up to 7.9 provides headroom for SSDs and faster conventional drives.

• Graphics performance is affected by the DirectX version supported by the GPU, the driver version used, and GPU performance. For example, if you have a DirectX 9.0–compliant graphics card using WDDM 1.1, your maximum score is 5.9. Higher scores are only possible with DirectX 10.x–compliant graphics cards that perform at about the same frame rate as in DirectX 9 mode. For mainstream DirectX 10 gaming, you will want a card with a WEI subsystem index of 5.0 or higher.

The easiest way to improve the WEI in a major way is to upgrade one or more of the major subsystems it rates. For example, replacing the video card can boost scores for Aero and for 3D graphics. Adding more RAM can boost memory scores. Upgrading to a faster processor can boost processor scores. Upgrading to a hard disk with a larger buffer, faster rotation rate, or both, can increase hard disk performance. Some upgrades, such as RAM and CPU, will boost performance in multiple areas. If you decide to upgrade your system, look at the following factors:

• Integrated video—If you can replace integrated video with a PCI Express (PCI-E) or AGP video card that uses a GPU listed on the Windows 7–compatible GPU list, you can significantly improve your Aero and 3D scores. Look for a unit with at least 128MB of RAM if you are primarily concerned about business graphics, or a unit with 512MB or more of RAM for 3D gaming. The latest nVidia GPUs have model numbers in the GTX 2xx series, whereas the latest ATI GPUs have model numbers in the HD 4xxx series. Higher model numbers generally indicate better performance, but see the manufacturers’ websites for details.

• Processor—Economy processors such as the AMD Sempron, Intel Celeron, or Intel Pentium Dual- Core have slower core clock speeds, slower front side bus connections to memory, and smaller L2 cache sizes than their full-performance counterparts (AMD Phenom, 64FX, 64 X2 or Intel Core 2 Duo, Core 2 Quad). However, a processor upgrade might also require a motherboard and memory module upgrade as well. Look at other upgrades first to improve your system’s base and subsystem scores.

• Memory (RAM)—Windows 7 runs best with at least 1GB of RAM available to Windows. Many so-called “1GB” systems, particularly laptops, actually share 128MB of RAM or more with the integrated graphics subsystem. Thus, for best system performance, consider upgrading systems that use shared video memory to 2GB or more of system memory. To determine the amount of memory actually available to Windows, type DXDIAG into the Instant Desktop Search box and press Enter. This runs DirectX Diagnostics. The System dialog box indicates the amount of memory available to Windows in Windows 7. The System Properties dialog box in Windows 7 now shows total system memory, including memory set aside for graphics memory. The difference between these amounts in Windows 7 is the amount of RAM used for shared video (graphics) memory.

• Hard disk drives—The best hard disks for desktop computers feature spin rates (RPM) of 7,200 to 10,000 and 16MB or larger buffer sizes. If your hard disk has a lower spin rate, smaller buffer size, or both, it’s limiting the performance of your system. If you’re considering a hard disk upgrade, keep in mind that new Serial ATA (SATA) drives are generally faster and larger than traditional PATA (ATA/IDE) drives. However, some older systems may have limited or no support for SATA drives. Laptop drives tend to feature lower spin rates, smaller buffer sizes, and smaller capacities than desktop drives.

Click the link Tips for Improving Your Computer’s Performance on the Performance Information and Tools page to learn about the tools provided in the Tasks list on the left side.