Pinging Router Fails 5% Of The Time?

Lately I've noticed that my internet connection has been less than stellar. I will be playing an online game or surfing the web, and every so often I'll freeze up or things just won't run smoothly. My network consists of the following...All of my computers and devices connect to a Cisco 16 port gigabit switchThe switch then connects to a Peplink 20 Dual WAN routerThe router connects to a cable modem as well as a DSL modemThe other day I was trying to diagnose the problem, as well as update the firmware of the router. While I was on the main "status" page, I noticed an error saying that I couldn't connect to the router. It quickly cleared and everything was working fine. This of course made me think that my issues have to do with my connection to the router, and not with the internet service itself. I then tried ping -t to two other computers on the network, as well as the router. After 5 minutes of pinging, the connections to the two computers had zero fails, while the router connection failed about 5% of the time. I ran the same check from the other computers on the network, with similar results.So, I know that the issue lies with the router (I think), but that's where my brainstorm ends.