Motorola 5101 disconnect issues

My Motorola 5101 currently a lot of modem reboots of  late when download large files. This problem started four days ago.  When I playing games online doesn't have any problem,only downloading large files does it show up.

1) I tried reset to factor default, didn't help

The modem in question about three years old, and don't doesn't splitter on it. I currently going to replace the modem (it due),but
I check to see if there other options to consider before doing that. As far as I know, it doesn't any connection problem in area,but maybe something is going on that I don't know about

Thank for an advise.