Link speeds limited to 100 Mbps
So I am trying to figure out how to get my computer to have faster speeds than 100 Mbps. My ISP recently upgraded us to 400 Mbps, I have an MSI MAG X670E Tomahawk motherboard that supports up to 2.5 Gbps and an R8500 Nighthawk X8 AC5300 Smart WiFi Router that I believe supports at least 1 Gbps normally and 2 Gbps with port aggregation (I'm also plugged into the 3rd port which is supposed to be the fastest). Both of the Ethernet cables, the one connecting my modem and router and the one connecting my router and computer, are cat 5e cables. I ran speed tests with my WiFi and have gotten between 430 and 480 Mbps, with my computer showing a 866/866 Mbps link speed on my WiFi.
I have attempted many different troubleshooting options listed around online and none have worked. At this point I'm assuming that there's something wrong with my cable that connects my router and computer. It's gotta be 15 or so years old and is really long, like maybe 50-100 feet.
So my question is, assuming no one has any other troubleshooting options to try, should I assume it's my cable? Is the long length to blame for the limited link speeds? Also, would I benefit from upgrading both of my cables to cat 6, if I go that route?
