This is one of those questions that should be really simple to answer, but isn’t.
I’m assuming you mean bandwidth, which isn’t speed, it’s capacity. Speed is the response time incurred in a round trip from source to destination and back, sometimes called latency.
Bandwidth is governed simply by the capacity of the links between you and the destination – their size and how much they are utilized at the time you measure it. That part is fairly easy.
*Perceived* speed, or how fast a connection feels is more governed by latency. If you click on a link, and see the response virtually immediately, it feels fast. If it hangs for even as much as half a second it feels slow. This is rarely anything to do with bandwidth.
Gaming, streaming and other forms of voice and video are particularly sensitive to latency and will perform badly if your latency is high regardless of how much bandwidth you have.