Connecting Ethernet cable from modem to router now slows down speed drastically.

[ThyAlex]

So we were using a wifi router/modem for a while a 2 in 1 device but the wifi range was horrible. So we bought an asus wifi router and set the old device into modem only mode. All my devices are running ethernet cords but for some reason my PC internet speed slows down from 8-15 when i plug it into the new asus router, And when i plug it back in to the modem i get my usual speed from 250-400 mbps. This problem only occurs with my pc becasue my roku, ps5, and smart t.v. are all using ethernet cords plugged into the new asus router with no problems. Any help guys ? 

Also idk if this helps but on the back of the motherboard where the ethernet port is there is a green light when it is plugged into the modem and then that light switches to orange when plugged into the asus router.

[Windows7ge]

24 minutes ago, ThyAlex said:

Also idk if this helps but on the back of the motherboard where the ethernet port is there is a green light when it is plugged into the modem and then that light switches to orange when plugged into the asus router.

Chances are this is an indicator that the link is negotiating down to 100mbps instead of 1gbit.

 

What happens if you connect the PC to another port on the router? Do other devices work fine on the same router port?

 

Did you verify that the router collected your public IP from the modem after you disabled it's router?

 

Have you tried booting another OS on this computer and seeing if the speed improves? Windows sometimes pulls this number...

[ThyAlex]

12 minutes ago, Windows7ge said:

Chances are this is an indicator that the link is negotiating down to 100mbps instead of 1gbit.

 

What happens if you connect the PC to another port on the router? Do other devices work fine on the same router port?

 

Did you verify that the router collected your public IP from the modem after you disabled it's router?

 

Have you tried booting another OS on this computer and seeing if the speed improves? Windows sometimes pulls this number...

yes i tried different ports on the asus router and i get the same problem 

and idk about the public IP but ill look into that rn 

and No i haven't tried any other OS