Problem
In addition to hyper-threading (i.e. multiple threads execute on a single physical CPU appearing as 2 logical CPUs) and dual-core technology (i.e. a single CPU socket that has more than 1 core appearing as multiple logical CPUs), chip vendors are beginning to release processors with more than 2 cores. I am considering purchasing a new SQL Server with multi-core processors to support a SQL Server 2005 Standard Edition deployment. What are the impacts when using a 4-core processor with SQL Server 2005 Standard Edition? Will I only be able to make use of a single physical CPU since Standard Edition is limited to 4 CPUs? Additionally, what is the overall licensing policy in relation to multi-core technologies with SQL Server 2005?
Solution
One key competitive licensing advantage of SQL Server is related to this exact question – for the purposes of both licensing and CPU edition support, SQL Server considers the number of physical sockets/CPUs, regardless of the number of cores on the processor. So, for example, if you are planning to deploy SQL Server 2005 Standard Edition, which supports up to 4 CPUs, that means Standard Edition will support 4 physical CPU sockets, regardless of the number of cores in each CPU. If you have 4 physical CPUs with 4 cores each, then your SQL Server Standard Edition deployment would have 16 logical CPUs to make use of. Additionally, even though you have 16 cores/logical CPUs, the licensing of this requires that you pay for only the 4 physical CPUs, not all 16 cores. This offers a very attractive return on investment (ROI) for any organization looking at the latest hardware with SQL Server 2005.
For additional information on SQL Server 2005 and multi-core licensing, reference the SQL Server Multicore Licensing Policy article.
Next Steps
- With these new CPU options, research these options with your hardware vendor of choice to see what opportunities are available with their latest and greatest servers
- If your applications are CPU bound and you are unable to tune the SQL Server and queries any further, then research the multi-core opportunities to meet your CPU needs
- Keep in mind the huge pricing advantage for SQL Server 2005 with support for multiple cores when you start to look at other DBMS’s in your environment or considering upgrading
- Special thanks to Chad Boyd from the MSSQLTips.com community for this tip.

Chad is an Architect, Administrator, and Developer with technologies such as Sql Server (and related technologies), .NET, Windows Server, and the Microsoft Clustering stack (MSCS, NLB, HPC). After nearly 5 years at Microsoft in a variety of roles related to pushing the limits of the Microsoft stack in many of the largest, most complex Sql Server installations in the world, he now provides consulting to many different customers and clients ranging from startup to Fortune 50. Most recently he has been spending much of his time as an architect at SpruceMedia, Inc., a startup firm in the Facebook/Social Advertising space (http://sprucemedia.com) and resides in the Redmond, WA area where he also spends a significant amount of time writing, talking, presenting and blogging about the data-related technologies on the Microsoft stack. Chad regularly posts Sql Server related content, tools, and advice with the MSSQLTips team and on stackoverflow.com at http://stackoverflow.com/users/169012/chadhoc. Chad can be contacted via email at chad dot boyd dot tips at gmail dot com.