Understanding Vista's Windows experience index

By Jay Dougherty Sep 8, 2007, 5:12 GMT

Washington - In the past, it was difficult to measure exactly how fast one computer ran Windows versus another computer.

Now, thanks to Windows Vista's new experience index, the guess work has been taken out of evaluating performance.

Understand the experience index, and you'll be ahead of the game when it comes to judging the performance of a new PC or determining how best to upgrade your existing box.

--- Experience index explained

Essentially, the Vista experience index is a numerical value that allows you to compare how well your PC runs Vista versus other computers. You can go directly to the screen that shows the experience index by holding down the Windows logo key on your keyboard and tapping the Pause/Break key. You can also get there by opening the Control Panel, clicking System and Maintenance, and then clicking System.

In the resulting System Information panel, you'll see the experience index displayed numerically within a square box with a bluish background. The words Windows Experience Index appear to the right of the box. You can click those words to open a detailed panel that breaks your experience index down into various components of the system.

When you first install Vista, a performance evaluation of your computer is done toward the end of the installation. It's at this time that the various subcomponents of your computer - processor speed, disk speed, graphics, and memory - are evaluated and given a numerical score.

The overall index - or the base value, as it is called by Microsoft - isn't the average of all scores presented but rather a number that represents the lowest score that any given component in your system has received. Vista experience index values can range from 1 to 5.9, with 5.9 being currently the highest score that a Vista computer can receive.

That means that although your processor and primary hard disk might receive scores in the 5.x range, if your graphics card scores a 2.4, your base Windows experience index - the one displayed prominently when you press Windows key-Pause - will be 2.4.

--- What the scores mean

There's more behind the five levels of the Windows experience index - 1.0, 2.0, 3.0, 4.0, and 5.0 - than simply numbers that allow you to compare your computer's performance to that of others. Each bump up the scale from 1 to 5 means that your computer satisfies some minimum requirement for a feature or level of performance that Vista offers.

A Vista experience index of 1.0 at any level means that the computer or component is capable of running Vista at a basic level only. If your computer rates anywhere in the 1.x range - especially when it comes to graphics - you likely will not be able to run Vista's Aero interface. A 1.x score for any component should mean that you either upgrade that component or think about getting a new computer altogether if you intend to run Vista long-term.

A score in the 2.0 range means you have a PC that will run the Aero interface - which is Vista's signature feature. But a rating of 2.x is considered marginal in terms of performance, and Microsoft notes in one of its design documents that 'performance issues may be noticeable.' Translation: think about an upgrade.

Computers that receive an experience index in the 3.x range are eligible to receive the Windows Premium logo, which means they can run with the Aero interface enabled by default. Performance of applications on such machines is supposed to be snappy. The only downside is that performance will suffer on these machines if they run two monitors rather than one.

Level 4.x and 5.x machines are the most desirable, and you should ensure that any new computer you purchase to run Vista scores somewhere in these ranges. You should also endeavour only to upgrade to individual components that can offer Vista experience index scores of 4.x to 5.x. Gamers and those involved in multimedia and graphics production, in particular, will want Vista machines that score in the 4.x and 5.x ranges, since these machines are guaranteed to be good at handling demanding, live-motion video and high-definition screens.

Level 6.0 is reserved for future use, Microsoft says, to reflect the performance of computers and components that are more powerful than those widely available today.

--- Using the experience index

So how can you put Vista's experience index to good use? First, it can be very helpful when purchasing a new PC or notebook, specifically when you can walk the aisles in a computer store and compare the performance of different systems. Just by scanning the experience index of various models, you can see at a glance which one will perform better than another - and in which particular areas.

This evaluative advantage is a first for Windows users; previously in order to gauge the performance of a PC, users had to rely on a subjective sense of how quickly specific operations completed.

The other way that the experience index is valuable is when you want to bring your computer up to a better level of performance. Thanks to the index's granularity - its rating of particular computer subsystems - you can see at a glance whether your graphics card, hard drive, memory, or processor is holding your machine back.