So I recently found out that I am paying for 100mbps but today I noticed that on wireless I am only getting 30,I contacted my isp and they said that my modem was causing the issue and capping the speed at 30mbps but I remembered that when I used ethernet I was able to reach 80-90 mbps, so I told them that information and they told me that it is an issue with my router and that it is no capable of sending signals to my devices to hit 100 mbps. At this point I do not know if the issue lies in my router or modem but I just want my 100mbps, my router is a netgear n600 (WNDR3400) and my modem is a surfboard SB6121.Do I buy a new modem or router.