Asgard weapons are significantly superior to the weapons of most other races in the Stargate Universe. The Energy Weapons of a single, aging Beliskner Class ship were capable of destroying several Goauld Hatak Motherships. These weapons were rendered less effective following the upgrades that Anubis installed onto his Ships (Anubis had acquired the knowledge to modify the Shields and weapons of his Ships as a result of the knowledge he had gained following his Ascension). However, the weapons and shields of the more advanced Asgard O'Neill-class ships were far superior to that of any Goauld Ship.These weapons were effectively utilized against Replicator ships of the Milky Way Galaxy. Four Ori warships proved capable of withstanding weapons fire from a single Asgard O'Neill-class ship at the Battle_of_P3Y-229. (SG1: "Revelations", "New Order, Part 1", "Camelot")
The technology used in these weapons was a closely guarded secret by the Asgard as they declined to equip any Earth ship, though the Asgard scientist Kvasir also allowed the SGC to borrow an energy weapon after a string of alternate SG-1s began coming through the Stargate from parallel universes, but only after they promised to return it. The borrowed energy weapon was powerful enough to pierce quantum realities. (SG1: "Ripple Effect") These weapons were later rendered obsolete by the Asgard plasma beam weapon, which is the weapon the Odyssey was equipped with when the Asgard upgraded the ship with weapons. Unlike the ion gun, the beam weapons were able to penetrate even the most powerful shields, including those of Ori warships and Aurora-class battleships although they were ineffective against the Super-hive.