XboxOne really supports 5Ghz?

This Support page about wireless network lists solutions and this information that may assist you.

Hi

Sorry but I don´t have headsets wireless... Then XBOX ONE don´t support wireless high velocity.

It's better a computer than console xbox ? are you sure ?

Hi

Sorry but I don´t have headsets wireless... Then XBOX ONE don´t support wireless high velocity.

It's better a computer than console xbox ? are you sure ?

The point I was trying to make was about signal interference.

If you can't connect your console with a wired connection, check to see if your home router supports dual-band connections (both 2.4-GHz and 5-GHz Wi-Fi connections). If your home router is dual band, try moving your Xbox One console to the 5-GHz router connection and move other wireless devices to the 2.4-GHz router connection. While 5-GHz Wi-Fi has shorter range than 2.4-GHz Wi-Fi, it can also have less overlap with other wireless networks and therefore perform better.

Troubleshoot downloads on xbox one

Here is a chart for the minimum speeds needed for gaming and streaming movies. (website link at bottom)

Think of it this way on your computer if you are going to speedtest.net it looks for the closest server to test off of normally not to far away.

If you are doing the speedtest through the consoles network settings they are more than likely pinging the servers in Seattle WA (MS HQ) so depending on how far away you are from Seattle you are more than likely going to see a slower connection speed than you would going on your computer that is looking for servers in your local area. 

But like what was previously pointed out your speeds are well above the minimum to be able to play online according to the chart below.

Link for minimum speeds

The Xbox One really does support 5GHz. It even supports 802.11ac, which the FritzBox 7490 also supports. You should however check the firmware, as the 7490 already supports FritzOS 7. 

However, if you have a lot of wireless devices connected to your 7490, be aware that the 7490 does not support "MU-MIMO" (Multi User-Multiple Input Multiple Output). For an explanation about the difference see this page here. 

To put it in laymen's terms: In theory, the FritzBox could transmit up to 1300Mbit/sec via 802.11ac wireless. However, with interference and distance to the router, this bandwidth is reduced. And if multiple devices connect to the WiFi at the same time, each device gets to transmit to the network "one by one" in a sort of "round robin" fashion, where all other devices have to wait for the one device to finish transmitting, so they can then get their turn. 

The question is I connect to the computer and my xbox, they are in the same place next to the modem and there is a lot of difference makes me think that it does not support it.

Computer: ping in 5ms Downlaod: 150mps & upload 15mbps

XBOX: ping at 16ms Down: 80mpbs and Up: 13mbps

It is too slow to play. How can I improve the speed?

Is it a FritzBox 7490 with firmware 6.51?

If you console and PC are "next to the modem" why you aren't using a couple of ethernet cables?

Nothing is better than ethernet connection.