F5F Stay Refreshed Power Users Networks Router problems with delayed internet speed.

Router problems with delayed internet speed.

Router problems with delayed internet speed.

S
Suhayb_10
Member
57
11-22-2025, 10:02 PM
#1
Router: TP-Link Archer C1200 AC1200 I own a separate modem and this router. My ISP promised a stable connection with speeds over 500 Mbps. Using the router, my download speeds drop to 70-80 Mbps, which is far below expectations. When I disconnect the router and connect only the modem, I see speeds of 400-500 Mbps—the guaranteed rate from my ISP. Is this router malfunctioning? Anyone have advice? Why does it slow down my Ethernet connection so much? (My PC has a gigabit port, so it shouldn’t be the problem)
S
Suhayb_10
11-22-2025, 10:02 PM #1

Router: TP-Link Archer C1200 AC1200 I own a separate modem and this router. My ISP promised a stable connection with speeds over 500 Mbps. Using the router, my download speeds drop to 70-80 Mbps, which is far below expectations. When I disconnect the router and connect only the modem, I see speeds of 400-500 Mbps—the guaranteed rate from my ISP. Is this router malfunctioning? Anyone have advice? Why does it slow down my Ethernet connection so much? (My PC has a gigabit port, so it shouldn’t be the problem)

S
Sqorck
Junior Member
47
11-29-2025, 06:14 PM
#2
Is your device linked via Wi-Fi? It seems like a 150mbps connection, which is typical for half-duplex links. If you're using cable, this shouldn't occur. I have one too, and I manage to reach close to a 1gbps uplink through it. (The C1200 really falls short in my view)
S
Sqorck
11-29-2025, 06:14 PM #2

Is your device linked via Wi-Fi? It seems like a 150mbps connection, which is typical for half-duplex links. If you're using cable, this shouldn't occur. I have one too, and I manage to reach close to a 1gbps uplink through it. (The C1200 really falls short in my view)

A
avi15
Member
167
12-07-2025, 01:23 AM
#3
You're using cable yes and also prefer a good Ethernet cable.
A
avi15
12-07-2025, 01:23 AM #3

You're using cable yes and also prefer a good Ethernet cable.

A
AdniTormar
Junior Member
18
12-11-2025, 02:59 PM
#4
Confirm your connection setup is correct. Ensure you have a stable cable between modem, router, and PC. Check the reported link speed in Windows Network settings.
A
AdniTormar
12-11-2025, 02:59 PM #4

Confirm your connection setup is correct. Ensure you have a stable cable between modem, router, and PC. Check the reported link speed in Windows Network settings.

M
McBroke
Member
168
12-15-2025, 06:32 AM
#5
I experienced the same issue! My ISP offered 300 Mbits, but my TP Link AC1200 router only delivered 100-120 Mbit for both wired and wireless connections. It looks like you discovered a workaround that works at full speed for you. On the router admin page, navigate to Advanced -> System Tools -> System Parameters. In the NAT menu, turn on the NAT Boost function. This should resolve your problem as well. Hope it helps!
M
McBroke
12-15-2025, 06:32 AM #5

I experienced the same issue! My ISP offered 300 Mbits, but my TP Link AC1200 router only delivered 100-120 Mbit for both wired and wireless connections. It looks like you discovered a workaround that works at full speed for you. On the router admin page, navigate to Advanced -> System Tools -> System Parameters. In the NAT menu, turn on the NAT Boost function. This should resolve your problem as well. Hope it helps!