Try this, it's something I wrote to automate a program that could be optimized on number of processors used:

create procedure num_processors

as

set nocount on

declare @numprocs int

create table #numprocs

(

id int,

colname varchar(128),

IV int,

CV varchar(128)

)

insert #numprocs

exec master..xp_msver

select @numprocs = IV from #numprocs

where colname like '%ProcessorCount%'

drop table #numprocs

return @numprocs

go

Hope it helps. It gets the actual internal processor representation from SQL Server so hopefully it is accurate.