should we replace the MVG510 modem with the 5268

The 510 is an ADSL2+ gateway, 2.4Ghz b/gn wireless with (4) T10/T100 Ethernet ports… best internet speed would be 18/1, most likely has less based upon copper distance from the Central Office (CO) or Remote Terminal (RT). Speed tiers before 2016 for ADSL2+ were 18, 12, 6, 3, 1.5 and .76… after 2016 changed to 18, 10, 5, 3, 1.5, .76. 

The 5268 is a dual band 2.4Ghz b/g/n AND 5Ghz n/ac wireless with (4) T100/T1000 Ethernet ports.

While providing better Wi-Fi at shorter distance using 5GHz the bottle neck is still the speed tier subscribed to of 18 or less. This is shared bandwidth with all devices connecting, if only have internet 6 or 3 the improved Wi-Fi performance is not going to provide faster speeds for multiple devices.

May want to check address online to see what is the fastest speed tier available for the address.

can check gateway stats using 192.168.1.254 to see max bandwidth and user bandwidth… please post stats if wish to know more.

thanks. Please see attached. it has been a really long time since I used DSL so I am a bit lost in all this but this is what my test showed.

If we are going to just leave it with the NVG G510, is there an extender you can recommend for that router for the 5268 for that matter.

did you get the speed test I sent question also do you recommend an Extender  that will work with either the NVG G510or D 5268