For consumers, Microsoft said, the advantage of such a model would be a lower price at the outset for a powerful PC. Computer makers would gain the ability to standardize on higher-end systems, it added. But the company admitted that the overall cost to the user might be higher. "Although the cost of ownership over the life of the computer may be higher than that of a one-time purchase, the payments can be deferred and the user can extend the useful life of the computer beyond that of the one-time purchase machine," Microsoft contended.

Key to the concept is something Microsoft called a "security module," embedded either in the hardware or provided as software, that would meter the computer's usage. "To make this model successful, a mechanism must be in place that supports a highly secure method of adjusting performance coupled with a secure, auditable measurement and payment scheme to allow a variety of pre-paid and post-paid mechanisms for capturing and settling highly granular, infinitely adjustable, performance variations," said the patent application.

The security module would also lock the PC to a specific supplier, perhaps an Internet service provider (ISP), much as a subsidized cell phone is locked to a specific mobile carrier for the life of a contract. "The metering agents and ... the security module allow an underwriter in the supply chain to confidently supply a computer at little or no upfront cost to a user or business, aware that their investment is protected and that the scalable performance capabilities generate revenue commensurate with actual performance level settings and usage," said Microsoft.

Pricing could be on an hourly rate, perhaps with different "bundles" priced according to the software offered and the hardware necessary to run that software. An "Office" bundle, for example, might include word processing and spreadsheet software that could access two of three processor cores and a medium level of graphics performance for, say, $1 an hour.

A "Gaming" bundle, meanwhile, would make available all the PC's processor cores and 3D graphics support for $1.25 an hour.