I got broadband 250 this summer (Cisco DPC3825 Modem) and I am experiencing download corruption with HTTP downloads. Other downloads such as torrents or steam work fine for the most part.
I find that any compressed files (zip, rar etc.) are coming up with CRC errors when I try to extract them. This also affects .exe files. Basically any download through the browser. Also Windows update sometimes is unable to download and must re-attempt.
I found a forum where another user was having the same issues with his shaw connection and he used HTTPS to download and it rectified the issue, however not all sites allow you to download this way.
I have tried all different browsers (IE, Firefox, Chrome etc.) and they all have the same issue. This is just a huge inconvenience as quite often I will have to download a file repeatedly to finally get one that is not corrupt.
So I have pored many hours into this over the past few months to no avail. Hopefully someone else here has encountered the issue and solved it.