Really slow library update

I recently aquired two RaspI 3’s for entertainment purposes. 1 of the 2 takes a very, very longtime to update the library. They are identical, both running the latest version of Openelec. Except, different brands of SD Cards.

The libraries in question are on NAS’es, about 700 Movies, 2000+ TV Show episodes. The first one I setup ran through the update in about 30 minutes. The second is still going, after 4 hours.

So, could the difference between SD Cards be the problem? Bad Raspi? Has anyone seen simular issues?

It’s a GB Network, 100mb Internet Service…

Thanks for any input.