As part of a new platform deployment I recently took delivery of a number of servers one of which was a DELL R900 with 4x 6 core processors. After a base install of Windows Server 2003 R2 x64 I attempted to install SQL Server 2005 Enterprise. Setup failed with the following error: The SQL Server service failed to start. For more information , see the SQL Books Online....
Microsoft has confirmed that on a computer that has a multicore processor, if the ratio of logical processors to physical sockets is not a power of 2, you cannot install SQL Server 2005. Microsoft SQL Server 2005 Service Pack 2 and higher fixes this. However it it not possible to slipstream a service pack into SQL 2005 install cd / dvd. A quick fix is to modify the boot.ini file and add /NUMPROC=1 to the boot options.
Install SQL Server 2005.
Install SQL Server 2005 Service Pack 3
Remove the /NUMPROC=1 from boot.ini and reboot.
SQL will now see all processors.