new router slower wired speed

Hello. I just received a new router from my ISP, an Asus DSL-AX5400. Everything on it works great except for a speed issue I am having trouble figuring out. I have a decent speed, for being in Australia anyway, and doin a speed test on speedtest.net with a wifi device I am getting 90Mbps however doing the same test with my PC which is wired I only get 49Mbps. prior to using the new modem I would get faster speeds over the wired connection. Can anyone help me figure out why this is happening?
 
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