Limit CPU usage without Resource Governor

Question

We have an SQL Server 2008R2 Standard Edition with several databases belonging to different applications on a 16 core server.

One recently introduced application is regularly executing expensive queries that lead to 100% CPU usage. Of course the other applications are reporting performance issues.

The Resource Governor seems like a suitable tool to put the reins on the rogue application, unfortunately it is only available in the Enterprise Edition.

Since the other applications are rather simple, I tried to get the problem under control by reducing the "max degree of parallelism" of the instance, so that a single query can not bring down everything. While that succeeded in keeping the CPU load at 50%, it did surprisingly nothing to keep other applications from being bogged down.

Now we have decided to move the databases for the new application to a dedicated instance, but what would be the best configuration for this instance? Should I keep the MAXDOP-setting, use a CPU-affinity mask or is there another option to limit CPU usage that I am not aware of?