High graphics jobs? Finale's not doing Augmented Reality 3D modelling or rendering the next Pixar film. It's putting some font characters and lines onto a page (which it used to do on much less powerful computers). 

Finale uses all the GPU that it needs. If there's something slowing Finale down, it's not a lack of GPU power.  I dare say it's not using all your CPU either.

I first ran Finale on a Mac+ — never been a resource hog.

If you load up the VI players (ARIA, UVI, Kontakt etc.) with a ton of instruments, that can use up CPU resources. There are ways to mitigate that including calling up new instances so that the OS will balance them among the cores. A single instance of a player uses one core only. Increasing the buffer size is often necessary, too. In both cases, the load is not caused by Finale but by the VI players.

Thanks for the info