Latency my 200mbps is clocking at 5mbps

I am experiencing severe latency issues with my 200mbps network. I had an Xfinity issued gateway, 4 months old, and just got it replaced because the technician told me that the problem is my modem and issued a replacement.

The speed is still the same. about 5mbps using Xfinity speed test.

Any ideas how I could rectify that without having to wait another 340 minutes for tech support?