XB max speed dropped

My xfinity XB10 modem dropped max incoming speed from 2Gb to 1.5Gb on download while upload is still at 2Gb.  I am on 2Gb plan and every thing was fine last month. It was giving 2Gb last month and dropped this month.

I restarted the modem multiple times to fix the issue, but no luck. I read online other users are having similar issues as well due to firmware updates or something like that. Something wrong with the equipment or the line. Please help.