I have gigablast but very slow download speed

okay so recently upgraded my service from 100 mbps to 1000 mbps.

i got a new modum shipped to me and everything, but using the speedtest available on the cox website my mbps download speed never seems to go above 40 mbps.

it seems that getting the upgrade has changed nothing. even when i had the 100 mbps speed my download speed never went above 40.