When you put the router between routers is it wireless or wired? Check to see if your firmware is up to date ans if not update it. I would re-set to factory and re-enter the minumun settings on the C2600 and try again, Be sure to use good quality Ethernet cable between the modem and your C2600 router and that the connections are good. For the WIFI, first try auto settings for channel selection and if poor results, select specific channels and widths.

@Kevin_Z 

 

Current network is: wallconnection -cable- C2600 -cable- PC And ofcourse some phones/tv etc connected to Archer on Wlan. This is the slow connection, 3-5mbits or so, but faster response time approx 15ms

 

The ordinary network is: Wallconnection -cable- Dlink router - cable - c2600-cable -pc and ofcourse all the things connected through wlan. This is the faster connection, 70mbits but slightly slower respons time approx 20-25ms. And ofcourse everything connected through wlan. 

 

ISP is Bredband2 and the bandwith is 100mbit

 

PC directly to c2600 by cable according to the test you linked to is 1.0Bbps

 

Not sure what you mean with operation mode, I have tried setting the channels manually and tried some diffrent channel width according to some suggestions found googling the issue and have used an app called "Wifi-Analyzer" to try to find the best channels

 

And in reply to ArcherC8

Firmware is up to date, I have tried to reset to factory but I am not sure what you mean with minimum settings, I have tried diffrent cables between the wall connector and the c2600 with exactly the same result 

 

Thank you both for taking the time to answer me and come with suggestions. Hopefully you might be able to help me solve this

@Kevin_Z 

 

Oh yes, it should ofcourse be 1.0Gbps and nothing else

 

I cant see the purpose of using it as an AP, isnt that basicly a way to use one router as an range extender?  

I dont want to use the old D-link at all, its quite old and not very good which were the reason for buying the C2600.

 

I might be able to get the wifi to work acceptable once i get the speed up on cable.

 

I cant for the life of me understand how this issue is even possible, why is the cablespeed higher when I add more equipment, it defies all logic for me. Its like having a car that can only drive 30km/h unless I tow another car behind it which would make the car much faster even though logic says it should be the other way around. I dont even know how to google the issue, in my head its just wierd but ofcourse, i dont know much about networks

 

I should have returned it long ago while i still had a receipt, But I had no patience and little time to spare at that time with a newborn beeing the priority. I doubt I will get a replacement now, probably been a year since i bought it and no receipt to prove it.