| title | Server Configuration: affinity64 I/O mask | |||
|---|---|---|---|---|
| description | Learn about the affinity64 I/O mask option. See when to use it to bind SQL Server disk I/O to a specified subset of CPUs. | |||
| author | rwestMSFT | |||
| ms.author | randolphwest | |||
| ms.date | 08/26/2025 | |||
| ms.service | sql | |||
| ms.subservice | configuration | |||
| ms.topic | how-to | |||
| helpviewer_keywords |
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[!INCLUDE SQL Server]
The affinity64 I/O mask binds [!INCLUDE ssNoVersion] disk I/O to a specified subset of CPUs, similar to the affinity I/O mask option. Use affinity I/O mask to bind the first 32 processors, and use affinity64 I/O mask to bind the remaining processors on the computer. If you reconfigure the affinity64 I/O mask, you must restart the instance of [!INCLUDE ssNoVersion]. This option is only visible on the 64-bit version of [!INCLUDE ssNoVersion].