1 gbps wired traffic

I have a wrt320N and E2000 routers, both are essentially the same and supposedly gigabit 1000mbps wired speed.  I now have a 1gbps connection and cannot get more that 70-90 mbps on a wired setup (using cat 6 cabling), but if I hook up the internet cable directly to a PC I can get 870mbps.  Does pppoe config affect wired traffic?  Stuck ..