The Supreme Kamehameha is fired with far more force and intensity than the Imperfect Instinct Kamehameha. Goku does not manipulate the Supreme Kamehameha's energy, unlike its predecessor, though it is extremely likely that Goku can do so.
Usage and Power
In the completed form of Ultra Instinct, Goku uses the Super Instinct Kamehameha two times against Jiren. While the Supreme Kamehameha was initially overpowered by Jiren's Power Impact with his hidden power awakened, upon being angered by Jiren attempting to kill Goku's friends the Supreme Kamehameha grew in power to the point that it was able to knock Jiren hard into the stage rubble, leaving the Pride Trooper severely injured and briefly incapacitated, though the strain of Ultra Instinct's extreme concentration drains Goku of his remaining focus and forces him out of the form.