Asus router - internet speeds dropped, but ok on ISP router


Well-known Member

I've got a strange one I hope someone might be able to help with.

I had fibre internet with Talktalk and was getting a reliable 60mbps for the last year or so. I don't use the Talktalk router, I use a BT Openreach modem connected to the master socket downstairs, hooked up to an ASUS RT-AC3200 router upstairs via a cat 6 network cable. I've had this set up for years, first with Plusnet, and then with Talktalk.

Recently I noticed that the download speeds have dropped to around 18-20mbps. Won't go any higher. Upload speeds are still fine at around 20mbps.

I didn't think much of it, and recently when I spoke to Sky they offered me a good offer to switch my fibre over to them, so I did. I figured the internet might sort itself out when I switched.

So after a week or so my internet switched over to Sky today. I received my Sky router but didn't intend on using it. I had to boot it up to get a MAC code and some other details from it, so I did. I carried out a speed test and got 60mbps. Great! So hooked up my Asus router, flashed to the Merlin firmware to get DHCP Option 61 MER activated and entered all the correct info. Internet is all working fine, but I'm getting 20mbps again!!

So any ideas what the issue could be? Could it be an issue with the modem or the router causing this slow down?

Basics are:

  • BT Openreach ECI modem connected to master socket
  • Cat 6 cable to Asus RT-AC3200 (now running Merlin firmware, but it was the same before on Talktalk)
  • Was previously working fine and running 60mbps on Talktalk, but then one day slowed to 20mbps for no reason
  • Switched to Sky Fibre. Same issue, still getting 20mbps on the Asus router.
  • Connect the Sky router and I get 60mbps!
  • Dead Asus router, problem with the cat 6 cable, or dead BT Openreach modem?
  • Should I try a new DrayTek Vigor 130 modem in place of the BT one?

Thanks for any help!



Well-known Member
Ah, I seem to have sorted it!! Turned of Quality of Service and the internet speed shot up. I think QoS was restricting web browsing to 20mbps and prioritising media streaming!

The latest video from AVForums

Podcast: Panasonic JZ2000 Final Thoughts - TV Calibration: Should you? And More...
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom