affinity64 Input-Output mask Server Configuration Option
The affinity64 I/O mask binds SQL Server 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 SQL Server. This option is only visible on the 64-bit version of SQL Server.