I have a Dell laptop and it has something called Rivet Networks Dynamic Bandwidth manager running in the background at all times recently and I think it is messing up the latency in internet connections for me.
Wi-Fi is extremely slow i.e. < 1 Mbps download speed on my Dell Inspiron . It turns out that the issue was caused by the SmartByte Network Service x64 being set to ‘Automatic’. Once the Startup type for this service was set to ‘Disabled’, my Wi-Fi network speed return to normal (around 25 Mbps). Not too sure what other flow-on effects this setting may have, but for the time being, this has certainly done the trick