Internet bandwidth and download capability

Hello everyone,

I have the following question and hope you can illustrate me in this matter.

I have a 512k dedicated internet connection. When I test it using for ex. Speedtest.net the average result show me that im receiving what im buying (0.5MB up/down) however I see that whenever I try to download a file the download rate is around 50KB/s.

1. Its only this really what I supose to get with this connection? or my ISP is restricting my download capability?

2. what is the average download rate that I should get?

Thank you so much for your support.

Best regards.