When you first start a broadband line, or upgrade to a faster service, there's a 10-day 'stabilisation period'. During the first 10 days, your line speed will fluctuate while the equipment at the telephone exchange works out the optimal speed for your line. This is based on many factors, including the distance you are from the exchange.
So running a line test during this period will not give you a true result. It may be too high, too low, or about right, you just don't know. You can only get a true result after the 10 days is up. Then, the most accurate way to test the line speed is to go to this address and follow the instructions:
If the speed is lower than you expected, take a look at our tips for getting the best speed from your broadband.