Standard broadband is also known as ADSL broadband. The speed you will see listed for standard broadband is ‘up to 17Mbps’, although you are very unlikely to get anything close to that speed in reality.
Watch out for how ISPs sell standard broadband as sometimes they don’t make it obvious exactly what type of broadband you’re buying. You may find that providers sell this slower type of connection as simply ‘Broadband’, while more expensive deals are specifically noted as ‘Fibre Broadband’.
Standard broadband uses copper telephone lines to make a connection to your home. Not only are copper lines slower than fibre optic ones, they are also weaker for interference.
Electrical interference is caused by many different things but the biggest offender is actually other users trying to access the internet through the same telephone cable.
Living in a crowded area, or being really far away from the telephone exchange, will massively increase the odds of frequent interference and your internet speed will suffer.
Fibre or cable broadband doesn’t suffer from interference and so delivers a far more reliable connection.