Are you running a Windows Server OS? I'm pretty sure you need to in order to run 4 CPUS. If you have the Pro version of Windows 7 or higher then you get a maximum of 2 CPUs. Regular non-pro versions of Windows have no multi-CPU support.
In any case, games aren't coded to scale across multiple CPUs like that and certainly not across 16 cores. Games will primarily run on your first CPU and it will be slow because those Xeon chips are 10 years old.