Very Slow Download Speeds from Apple Applications (Safari and Mac App Store) After I restored my computer to a clean reinstall of El Capitan, I have experienced incredibly slow download speeds in Apple applications only (Safari and the App Store). I tested downloading a file in safari, and I got around 256 kilobytes per second, but when downloading the exact same file with the exact same internet connection, I got much greater download speeds of around 5 to 6 megabytes per second. The same thing is happening in the App Store, with download speeds averaging around 256 kilobytes per second. 

I have tried changing the DNS to both Open DNS and Google Public DNS, and none of them seem to fix the problem.

Again, I am having extremely slow download speeds only in Apple applications. (Strangely enough, browsing speeds are still very fast. Only download speeds are slow.) This is a very strange problem and I have no idea what is causing them.

Please let me know how to fix this.
Seeing as others are mentioning this issue might be related to a specific ISP, try enabling a VPN and re-running the download.

This mightn't be a long-term solution, but it should help you identify if the issue is the ISP performing traffic shaping App Store packets.