Not getting full internet speed after the free speed upgrade

I recently noticed that the connection speed of my Performance Select plan changed from 100mbps to 200mbps. I then reset my Arris SB6183 cable modem, my speed didn't increase. It is still the same as before, which is about 94mbps (after connecting my laptop directly to the modem). I did some research and thought it was a problem with the Ethernet cable, the cable is a cat5 enhanced cable, so getting to a 200mbps shouldn't be a problem. I called Xfinity tech support, they said it's a problem with my modem, but from Xfinity's website (http://mydeviceinfo.xfinity.com/), it says my modem is capable of handling 200mbps speed and there isn't any setting at all. So I don't really know what is going on. Got any ideas??