I'm on a 15mbs-rated DSL and consistently experience 13mbs. Using MS Edge browser, GT pages download almost instantaneously for me. So yeah... it's probably your browser or your provider. That said, when things slow down for me a I find a modem reboot brings back the speed 90 % of the time.
Good luck.
edited
"It takes a lot of devotion and work, or maybe I should say play, because if you love it, that's what it amounts to. I haven't found any shortcuts, and I've been looking for a long time."
-- Chet Atkins
-- Chet Atkins