Go to your PC or laptop and determine your optimum size (MTU) that can be sent in 1 lump and not 2 will optimise your bandwidth and login potential.
Its your router that does this.
Go to cmd.exe
enter / type ping google.com -f -l 1472
Change by 1 up / down and find maximum number / size YOUR router can ping.
For me it was 1474. Then for MTU it has a 28 bit header, so your MTU = this number + 28.
Hence for my router BT hub 5 UK = 1474 (test) + 28 gives optimum MTU = 1492.
If you put in the lower number it will also work on Ps4, but your bandwidth on Ps4 will be down a small amount