Synology DS-1512+ vs. DS-718+ (hardware) transcoding capibilities

Hi guys. Hope to have som insight on this.

I'm currently running Plex on my DS-1512+ but as many others NAS it struggles with transcoding.

I just switched to the 64-bit Plex server and have enabled hardware transcoding in the system settings.

But is the 1512+ capable of during hardware transcoding at all?

I've thought about switching to a 2-bay NAS as I don't use that much storage and the DS-718+ could be a good candidat.

How big a performance improvement Plex-wise would I gain from going from the DS-1512+ to the DS-718+?

The DS-1512+ rocks a Intel Atom D2700 dual core CPU and the DS-718+ a Intel Celeron J3455 Quad core.

Thanks in advance guys.