File this one under "N" for "No sh*t, Sherlock".....Wi-Fi slows down your broadband speed.

And whilst that news isn't all that shocking, hence the mocking opening sentence, the fact that we can lose almost a third (30 per cent to be precise) of our broadband download speed is somewhat surprising, and very annoying.

Quality of Service analyst Epitiro came up with the figure, and also stated that we are likely to experience a latency of 10-20 per cent when using Wi-Fi as well.

“Our data shows that connectivity over Wi-Fi degrades broadband performance considerably in typical circumstances.” said JP Curley, CTO Epitiro. "Consumers who are experiencing performance issues with Wi-Fi should take steps to improve their home environment or connect directly via wired ethernet.” 

So, if you're wanting to stream HD content, or perhaps indulge in a bit of Xbox Live-ing, then your Ethernet is likely to be your best bet.

The figures were based on an analysis of 14,001 panellists from November 2010 to February 2011 in UK, USA, Italy and Spain.