So 6 then.
In that case, you can try 6, 9 or 12 as maxdop, see which works best for you (calced as 1x, 1.5x and 2x the number of physical cores/NUMA node)
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability