Hard wired connection lag spikes

I've been getting terrible lag spikes every 5 to 10 seconds making playing games impossible.I thought it might have been my router so I wired my PS4 straight up to the Ethernet and it still happens. The Ethernet comes out of the wall into a little black box with a power supply then out with a cat5. Tried connecting my computer and it does the same thing as well on games. Any thoughts on what it could be? Can that black box go bad? ( Not sure what it's called) also I can watch high def movies just fine it's just the games that get the lag spikes. I normally get 22 Mbps download and 4 ish Mbps upload on my connection
 
Most likely the black box is your Modem from the ISP -- complain to them.
 
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