In my systems settings there's a tab where you can set Effect Handeling.

Ever since I installed the DC30+ codec it's changed all the settings to 'effects handled by DC30+' instead of by Final Cut Pro.

Is there some advantage to having DC30+ do this or should I change everything back to FCP?

Thanks!

The advantage should be that the hardware is doing all the
calculations instead of your main processor, this should increase
speed and free your main processor to do other things. You
should see decreased rendering times when effects etc. are
involved.