Thanks for reply I'm on 50mb so plenty speed =2 play stations and 4 phones +1 pc ,
Kids moaning at me they are lagging.
Try to leave PS4 and your box connected to the internet only,and see if PS4 lags then.
Also if all those devices are active at the same time,that may damage the runtime.
Also something that you can do:
Sometimes there are modem problems (or simply setup problems)that are really hard to notice.
Best thing that you can do is contact your broadband support.