Is the RT-AC88U powefull enought to handle transmission?

I've a RT-AC87U, and I have transmission installed on it. The problem is that the download speed is so unestable (I've got 50Mb/50Mb fiber conection). Using a Synology for download with same torrents is perfect. My questions is ... as RT-AC88U is 0,4Ghz faster and has 256mb more RAM ... does it worth it?

Regards.

PS: I'm downloading the files in a USB 3 pendrive (more than enought for the 6.5MB/s of my connection).