ASUS ZenWifi XT8 Issues - Throttled Speed

[RSR888]

Hi everyone,

I recently purchased a pair of ASUS ZenWifi XT8 mesh routers to improve WiFi coverage and speed across my home. I’m on Sky Full Fibre Gigafast FTTP and connected the primary router via Ethernet directly to the fibre box. The setup process in the ASUS app went smoothly, and I was surprised to see I had internet access immediately without having to enable IPv6 or enter DHCP 60 credentials.

However, I’ve encountered an issue: the speed from the ASUS router is capped at around 90Mbps, which is far below my expected speed. For reference, when I reconnect my Sky router, I’m consistently getting 911Mbps, as confirmed in the Sky app.

Here’s what I’ve tried so far:

1. Enabled IPv6 on the ASUS router and entered the DHCP 60 credentials manually – no change in speed.
2. Rechecked the fibre box connection and cables – no apparent issues.
3. Tested with the Sky router to confirm the incoming speed is fine.

I’m scratching my head trying to figure out what could be causing this bottleneck. Has anyone here experienced something similar or have any suggestions for resolving this?

Thanks in advance for your help!

[Chrisee]

@RSR888 most likely explanation is that the Ethernet port is configured to be 100Mb/s (aka Fast Ethernet) rather than 1,000Mb/s (aka Gigabit) as thst would explain your speeds as you havecto allow roughly 8% for network overheads. 

It could be the cable from the ONT so use the same cable as you do for tge Sky hub. To get gigabit speeds you require at a minimum a Cat5e cablecwith all 8 cores connected. Old Cat5 cables may only support the slower speed. There is no evidence Sky throttle third party routers .Ofcom would stamp all over them if they tried that.