Have a PS4 connected via a TP Link Powerline and have been seeing weird degradation of the connection through testing over a short period of around 30 minutes.

Basically was seeing some lag and tested the internet connection using the pretty crappy built in PS4 tool. I was getting around 3.2mbps DL and <1mbps up.

Swtiching the powerline off at the wall and back on again fixed it and it was back up >50mbps.

Running tests every couple of minutes and it got slower and slower every time until it 'peaked' at the numbers I was getting at first. Tried the same thing with the Ookla speedtest using the PS4 browser and got same results with a ping peaking at 199ms .....eek!

Via a laptop and pinging bbc.co.uk

Immediately after switch off/on:-

C:\Users\brucej>ping bbc.co.uk

Pinging bbc.co.uk [151.101.64.81] with 32 bytes of data:
Reply from 151.101.64.81: bytes=32 time=28ms TTL=57
Reply from 151.101.64.81: bytes=32 time=24ms TTL=57
Reply from 151.101.64.81: bytes=32 time=19ms TTL=57
Reply from 151.101.64.81: bytes=32 time=23ms TTL=57

Ping statistics for 151.101.64.81:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 19ms, Maximum = 28ms, Average = 23ms

10 minutes later:-

Pinging bbc.co.uk [151.101.128.81] with 32 bytes of data:
Reply from 151.101.128.81: bytes=32 time=122ms TTL=53
Reply from 151.101.128.81: bytes=32 time=62ms TTL=53
Reply from 151.101.128.81: bytes=32 time=166ms TTL=53
Reply from 151.101.128.81: bytes=32 time=102ms TTL=53

Ping statistics for 151.101.128.81:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 62ms, Maximum = 166ms, Average = 113ms

20 mins later

Pinging bbc.co.uk [151.101.128.81] with 32 bytes of data:
Reply from 151.101.128.81: bytes=32 time=128ms TTL=53
Reply from 151.101.128.81: bytes=32 time=70ms TTL=53
Reply from 151.101.128.81: bytes=32 time=25ms TTL=53
Reply from 151.101.128.81: bytes=32 time=124ms TTL=53

Ping statistics for 151.101.128.81:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 25ms, Maximum = 128ms, Average = 86ms

What could be causing this? I know Powerlines are not the best but it's always been pretty robust. 

Admittedly we live in a busy family home with multiple things all leeching off the connection but this is at night with most devices switched off.

Worth mentioning that the wi-fi connection seems pretty stable but has shown to be unreliable when gaming.

Keep thinking I'd like to pick up a new router (on virgin superhub) to give me some better control of the network. I'm a bit of a Networking luddite so any advice is welcome - thanks