s33 slow speed

For firmware updates, DOCSIS standards dictate that the service provider must distribute firmware updates to cable modem devices.  The end-user cannot simply install an update like most other network-enabled devices.

ARRIS develops the software update and makes it available to service providers.  The service providers qualify, test, and distribute the software update to devices on their network.  ARRIS has limited control or visibility on distribution by the service providers.

Are you checking the speed through Wi-Fi or by connecting the modem directly to a computer?

Could you please provide the name of your internet service provider?

Ensure the Ethernet cable is connected to the 2.5 gigabit port and directly to a computer, then try running a speed test again.