That's a spike not a drop, drop would be the other way around.
Which game(s) are you experiencing this in and is it affecting anything else that isn't a game?
If you could go to http://192.168.0.1 and click "check router status" below the password box and copy your downstream and upstream stats, and your network log here that may be of help in determining what the issue is (making sure to remove/obfuscate any MAC addresses or instances of your public IP address in the logs before posting.)
I also recommend setting up a BQM graph (https://www.thinkbroadband.com/broadband/monitoring/quality) as that may be helpful in narrowing down and getting a clear picture of the issue. If you do that and the bar is showing all red you'll need to enable WAN ICMP echo requests in the Hub control panel.