As AMD and Intel prepare to ship new processors that combine multiple CPUs, or cores, into a single package, Microsoft has announced that it will continue to count processors rather than cores for per-processor licensing of its software products. The announcement that the transition to multicore processors will not increase licensing costs allows customers to begin planning the acquisition and deployment of dual-core systems now, but in the future, multicore performance improvements might force some changes.

Hyperthreads, Cores, and Processors

Processor manufacturers find themselves between a silicon-based rock and a hard place—customers continue to demand more powerful processors, but power consumption and heat dissipation problems limit the density and clock speed that manufacturers can squeeze from their processors.

One solution is to enable processors to do more work with each clock tick by enabling them to run multiple instructions at the same time. For example, Intel’s hyperthreaded processors run multiple streams of instructions at once. However, all streams of instructions running on a hyperthreaded processor still share some resources, such as the processor’s onboard cache. Conflicting access to these resources limits the throughput of the processor.

The next generation of processors will improve support for multiple instruction streams by including more than one complete core on a single processor chip. Each core on the processor will have some dedicated resources, such as memory cache. The result is a single processor, usually running at a slower clock speed to minimize power consumption and heat output, that offers between 125% and 140% of the performance of today’s single-core processors.

A system with a single dual-core processor will not be as fast as a two-processor system. However, due to savings generated by using less power, and creating less heat, dual-core processors are expected to gain quick acceptance: Intel estimates that by 2007, at least 80% of the Intel chips used in servers will have multiple cores.

Multiple Cores Won’t Change Licensing

Software generally runs on a dual-core processor similarly to the way it handles a system with two independent processors. Therefore, some enterprise software vendors have elected to treat each core as a processor and require two per-processor licenses for software running on a dual-core system.

Historically, Microsoft has not used changes that increase the processing throughput of a single processor to trigger a licensing change. For example, Microsoft did not change its licensing practices with the advent of Multimedia Extensions (MMX), which sped up streaming media processing, or hyperthreading, which can make a single physical processor appear to the OS as two processors. For now, Microsoft has decided to continue this trend by deciding that processors, not processing cores, should drive per-processor licensing counts.

Thus, a customer running SQL Server 2000 on a server with four standard (single-core) processors would need one Windows Server 2003 Standard Edition server license and four per-processor licenses for SQL Server. If the customer upgrades the server to a computer with four dual-core processors (a total of four processors but eight cores), the licensing would be the same.

Microsoft does not anticipate that its licensing decision for processors with multiple cores will necessitate major changes to either End User Licensing Agreements (EULAs) or Product Use Rights (PURs).

As multicore processors improve and begin to offer processing throughput that rivals that of multiprocessing systems, Microsoft might have to review this licensing decision. But for now, Microsoft seems to hope that the improved price-performance of multicore processors will sell more Windows-based servers and thus more licenses overall, and will help differentiate Microsoft from competitors who charge a premium when their software is running on multicore technology.

Resources

For a comprehensive analysis of Microsoft’s licensing programs, see the Dec. 2003 Research Report, "Understanding Microsoft Licensing."

Microsoft recently updated its licensing Web site. For information on the new site, see "Support, Licensing Web Sites Updated".

Microsoft’s licensing site is located at www.microsoft.com/licensing/default.mspx.

Intel processors are described at www.intel.com.

AMD processors are described at www.amd.com.

For a list of the most recent Directions on Microsoft coverage of licensing topics, see the Recent Changes to Microsoft Licensing page.