The ISP or as it is known, the Internet Service Provider, claims to have up to 100GB downloads and up to 20gb uploads depending on which service provider you are using. If you notice it is always UP TO! The reason for this is you will be on a shared connection, and it can be a 30:1 or maybe 50:1 depending on your ISP.
Now if you had a ratio of 50:1 and all 50 users was downloading a large file at top speed, well it just wouldn’t be the case. You are set a specific bandwidth rate, unknown to you, but the more people that take up the speed the lower connection initially it will be for the end user.
The best way to check your speed it to try test internet speed. Check the results, at different times of the day. Every 4 hours within a 4 day period and get the avaerage speed and take some screenshots. Approach your ISP nd they may be able to reduce your connection ratio.
Some ISP’s have fiber optic cables, which are like glass strings underground that produce very fast speeds. but most people have the wired connection via a wire under your house close to the exchange. This also depends on your connection speed too. The further you are away from the ISP exchange the worse your connection will be unfortunately. The best way to optimize your connection is to monitor things you are downloading, and keep it to a minimal.