Wired (ethernet) connection drops occasionally while wireless connection always works.

Windows 8.1 and Xfi router (1gb). Ever since upgrading to the Xfi router the wired connection to the desktop drops occasionally. It could be several times a week or not at all for several weeks. All along the wireless connection works. I never had a dropped connection with the previous Xfinity router. A restart of the computer fixes the problem until the next connection drop.  A tech support telephone call was of no help. He suggested a modem swap which I might try. I did change the ethernet cable which didn't help either. Any suggestions?

Thanks,

Len