I have been unsuccessful locating information about the maximum number
of CPU's SQL Server 2005 Enterprise supports.
However I did find info in a document about configuring a fail over
cluster solution. It said 4 CPUs, but it is unclear how that works out
with multi core processors.
Is it 4 sockets? So with a quad core quad socket we could go have a 16
core system?
BTW the chart shows the CPU count jumping to 64 CPU's under Server
2003 Datacenter.
TIA

For licensing purposes SQL Server 2005 counts only physical CPU's,
regardless of whether they are hyper-threaded, dual-core, quad-core, etc.
Also, SQL Server 2005 will use all of the logical CPU's that are present
(based on the physical CPU count limitation).

See more details in the SQL Server Multicore Licensing Policy:
http://www.microsoft.com/sql/howtobuy/multicore.mspx

As for the physical CPUs supported by the different SQL Server 2005
Editions, here it is:
- Express - 1 CPU with multicore support
- Workgroup - 2 CPUs with multicore support
- Standard - 4 CPUs with multicore support
- Enterprise - Unlimited CPUs with multicore support

Have in mind that SQL Server will see only as many CPUs as the OS supports.

HTH,

Plamen Ratchev
http://www.SQLStudio.com