Will your PC keep pace with Vista?

How does Windows Vista love thy computer? Let it count the ways.

Microsoft is building into the new operating system a tool that will rate a PC based on how well it is running and on how much it can take advantage of Vista's capabilities.

The "Windows Performance Rating," which can be seen in the latest test version of the operating system, evaluates components such as the processor, the memory, the hard drive and graphics cards to come up with an overall score.

The rating appears in a large blue circle and can be seen in multiple places in the operating system, though Microsoft has said little about what exactly the rating signifies. The main rating is on a scale of 1 to 5, but individual components are also given a "sub rating" on some other, unspecified range.

"The idea behind the Windows Performance Rating is to help average consumers easily understand their Windows Vista PC's overall performance, and to simplify the process of determining whether certain software applications will run smoothly based on their system components," Microsoft said in a statement provided to CNET News.com.

Computer makers and retailers would then be able to use that as a tool to help explain, in general terms, the capabilities of a particular machine. Software makers would also be able to specify the type of PC needed to run their software.

A Sony Vaio laptop on display at last week's Intel Developer Forum, for example, scored an overall rating of 3. The PC had an Intel processor and 1GB of memory, which earned sub-ratings of 5.6 and 5.5 respectively. A desktop on the IDF show floor with Intel's Pentium D 940 processor and 2GB of unspecified memory also received a 3, with the processor rated at 5.6 and the memory at 5.5.

Microsoft declined to provide details of its rating methodology, noting that it is still working on the grading system.

"This capability is still under development, so the current experience with the Windows Performance Rating may not be indicative of the final experience," Microsoft said. The company promised that the feature would continue to be enhanced in future test versions.

Vista's performance ratings will be primarily useful to customers before they make a purchase, said Roger Kay, the president of market analysis firm Endpoint Technologies Associates.

The ratings could be a tool for salespeople in retail outlets, for example, to demonstrate how well systems would run Vista and related applications, Kay said. But if the buyer doesn't find out about the rating until they get their PC home and start playing around with it, it's harder to understand the benefits, he said.

Set scale?
An open question is whether the system rating is a fixed score or whether it might change over time, as hardware advances. There are challenges whichever route Microsoft takes. If adjustments are made, then the rating for a particular setup will decline, and consumers may feel their PC is losing steam. On the other hand, if the ratings don't evolve, improving technology could eventually lead all machines to score a 5.

As for systems slowing down, that's an issue that Microsoft is already trying to tackle. In the past, machines actually have lost significant performance as more software loads at startup, hard disks become fragmented and other features "gunk" up the works. With Vista, though, Microsoft has added several features that aim to keep the PC from bogging down over time.

It is unclear how large a factor these ratings will be for PC makers as they plan their Vista lineup.

Sam Bhavnani, an analyst at Current Analysis, said that, provided the rating system can be easily understood, it could give computer makers a new way to tout the performance of machines.

"It would make it easier for them to advertise their systems as 'good,' 'better,' 'best,'" Bhavnani said. It would mean the prospective buyer wouldn't have to compare the