slow internet on computer via router

[KarlF]

Hello.  I have a strange problem with my cable internet.  

It is slow on laptops but works fine with smartphone.  I have tried speedtests with multiple laptops and with my smartphone (with mobile connection turned off and connected to wifi).

When connected via wifi...
smartphone gets download  speed of 519 Mbit/s
laptop gets download speed of 13 Mbit/s.  I get similar speed on 3 different laptops running chrome and similar with firefox.  

when i connect smart phone to mobile network instead and do a hotspot  I get...
smartphone gets download  speed of 40 Mbit/s
laptop gets download speed of 35 Mbit/s. 


So, what i seem to find so far is this has specifically to do with the connection of a laptop to the router.  The laptops all go slow when connected o router but behave normally when connected elsewhere.  The phone also gets normal fast internet speed when connected to the router.

Any idea what is happening and how to fix it?  is this a router problem?  something else?

This has been off and on for a year now and i already replaced the router once, which seemed to temporarily fix it.  The router has an identification code: TG3442DE 

[KarlF]

Also, if i use my phone as a kind of "repeater", connected the phone to wifi and my laptop to the phone, i get high speed on the phone and improved, but still slow speed on the laptop... about 35MBit/s instead of 10 to 15 Mbit/s.  I am not sure if the limit then is something with the router or the hotspot on my phone

[KarlF]

I see that this is likely a limit on my smartphone's hotspot.  in other words, there is some limiting problem specific to connecting a laptop to the router, which has been a problem with this router and the previous one.  What could this problem be?  Is there a solution other than going to another internet service provider?

[RobertP]

try to disable 2,4 GHz Wifi in router settings

[KarlF]

how do i access router settings?

[RobertP]

described here:

https://www.vodafone.de/hilfe/router/station.html?accordion=einstellungsseite

[KarlF]

I was able to access the settings and turned off the 2.4 GHz wifi, but that didn't change anything.  any other ideas?

[RobertP]

unfortunatelly not  😞

except switching from Vodafone Station to Fritzbox

[KarlF]

More information... my computer's wifi does not seem to support IPv6.

Is this a problem? 

[RobertP]

then activate IPv6 in WiFi adapter settings and check results