Customers across Europe are getting broadband speeds 25% slower on average than that advertised by their service providers, a European Commission report says.
The study suggests the average speed in Europe is 19.7Mbps.
Service providers routinely advertise speeds "up to" a certain amount, which most consumers will not get.
The EU wants to get all households on speeds of at least 30Mbps by the end of 2013 and half on 100Mbps by 2020.
The study analysed broadband speeds from nearly 10,000 households around Europe. It ran 75 million tests, generating three billion pieces of data.
Cable broadband services came the closest to advertised speeds, at 91.4%, while fibre users got 84.4% of advertised speeds.
Beefed-up ADSL services fared the worse - getting just 63.3% of advertised speeds.
This is because they are run on copper phone lines that offer slower speeds the further people live from the exchange.
The UK government has announced it wants to get fast broadband to 95% of the population by 2017 and will use wireless and 4G to extend this to 99% by 2018.
"Fast broadband is no longer a luxury and is now just as essential as a reliable electricity supply for UK consumers," said Dominic Baliszewski, from website broadbandchoices.
"We shall see exactly how realistic these targets are. With Ofcom putting current super-fast availability at 65% of the population, there is still a long way to go."