Slow download speed on wired connect

As mentioned above, Try a wired connection to help with the download speeds, If that does not help and you are still experiencing slow download speeds your Internet Service Provider could be throttling your speeds for high bandwidth downloads

I am using a wired connection and when I did the speed tests, my download speed went up 50 Mbs but when I looked at the speed the game was actually downloading at, it was still mindbogglingly slow.

Hi - I'm having the same issue. I was in the preview program but don't have the app on the new Halo Xbox. I'm also having very slow download speeds - wired connection with average speeds of 70/50 normally (and on everything else connected).

"I have tried using a cable..."

Hello, are you referring to an ethernet cable? I live in Australia, and my download speed when using a wired (or ethernet) connection is only 18mbps. By modern standards, that's quite slow, but you've just said your download speed is 3mbps! For all intents
and purposes, wired is the way to go, and I've only encountered connection or download errors when the signal is compromised. If you haven't already, try reconnecting with an ethernet cable, and then checking your download speed from network settings to see
if it doesn't improve the speed!

This support page Explains slow game or app downloads.

Is it at all possible for you to go to a friends place or somewhere you can connect console (wired) to a network with fast speed and do your downloads?