The Asgard possess a level of technology rivaling that of the Ancients and the Ori, though they have clearly surpassed even them to a certain degree, which is extremely impressive, taking into account they are a much younger race. With the exception of a plague, the Ancients had at least 50 million years to evolve without constant threats, until 10, 000 years ago, when the Wraith made its presence felt. Losing the war despite their highly advanced technology, the Ancients/Lanteans had no other choice than to return to Earth to avoid certain extinction at the hands of the Wraith. Many of them ascended.
The Asgard however began exploring the galaxy some 100,000 years ago. Enemies vastly superior to the Tau'ri when they begun using the Stargate, such as the Goa'uld, were no threat to the Asgard, and the Asgard advanced very quickly.
Over ten thousands years ago, an Asgard named Famrir was temporarily a host to Ra. Even though the symbiote was removed and his body restored to perfect health he became mad and together with his fellow Asgard forced the surviving Goa'ulds to submission. Much to their hatred and unwillingness, combined with their nature of malevolence and power hungry nature, they were forced to kneel before the Asgard to avoid extinction. The Asgard did however become occupied elsewhere, in another galaxy. This allowed the Goa'uld to be the dominant force in the Milky Way for centuries, as all they had to do was to avoid attacking planets still protected by the Asgard.
If the bodies of the Asgard hadn't suffered from the ill effects from countless generations of cloning they could probably have ascended, if they so desired. The Tau'ri are now the only race which has access to the entirety of the knowledge and technology of the now extinct race; however it will likely take them decades, maybe even centuries, to fully understand and put to widespread use. Thor did however work on an extremely advanced database, containing all the knowledge of the Asgard, and holographic representations of himself and other Asgards. Though among the absolutely most advanced piece of technology of its kind, it's very user-friendly. Even persons with very limited knowledge of the technology are able to use it without much difficulty. Among other things, it was created so the Tau'ri would be able to understand the extremely advanced technology much faster, since they certainly didn't have centuries to find ways to defeat the Ori and get the upper hand on the Wraith and Asurans.
Thanks to Thor's hard work, the Tau'ri could quickly adapt certain technology very crucial at the time (the battles against the Ori and the Wraith). Thanks to brilliant scientists such as Colonel Samantha Carter, the newly constructed 304's were quickly integrated with the latest Asgard technology, such as weapons capable of easily defeating the most powerful enemy battleships, incredible shields (when properly powered able to withstand virtually anything), extremely advanced beaming technology, sensors, holographic technology and the most advanced hyperdrives known to exist.
With all those upgrades, the previous Earth vessels equipped with railguns, missiles and outdated Asgard shields, went from being mid-level at best, due to inferior weaponry, to the most advanced ships in the known universe (the Odyssey and the Daedalus, for example). Thor, as a high-ranking member of the Asgard, declared the Tau'ri the fifth race, having the full authority to do so, as his race were among the alliance of the Great Four races. With these new ships, the Tau'ri could easily deplete the powerful shields on the Ori Warships and destroy them with a handful of beams, or even less. The shields on the Aurora-Class warships, the most powerful ships in the Ancient fleet, are unable to offer protection against the Asgard Plasma Beams, succumbing to these weapons in just 2 hits, and their Drones unable to penetrate the Asgard shields. Even the huge Wraith Hive Ships could be seriously damaged with a single, well-aimed beam, and destroyed with a second one.
With the enormous amount of information gifted to the Tau'ri by Asgard, combined with the moderate (but quickly improving) understanding of Ancient technology, the Tau'ri (as Thor stated) "Are the only hope to preserve the future".
Dependent on neutronium, the Asgard possessed a level of technology vastly superior to that of Goa'uld and many other races throughout the universe. Indeed, the only races with a level of technology comparable to the Asgard are the Ancients, the Ori, and possibly the Nox and Furlings. Their ships were capable of traversing thousands of light years in minutes, and their shields could take multiple hits from Ori warships while remaining undamaged, which had never been done before. Shortly before their extinction, the Asgard developed energy weapons capable of, with repeated strikes, defeating the shields of Ori warships, which had previously proved impervious to everything except the unstable vortex of the Ori's own Supergate. They had also mastered advanced transportation and holographic technology.
A display of the incredible intelligence and understanding of an Asgard mind could be witnessed when Thor investigated Jack O'Neills creation and within a mere hour or so already knew exactly how the Ancient device worked, and how to improve it and Kvasir was fully aware how the Sangraal operated, and explained it to Samantha Carter, who admitted it was well beyond her understanding. The Asgard have honored the Tau'ri on more than one occasion, naming their most advanced battleship "The O'Neill" and an advanced research vessel "The Daniel Jackson".
They lost the ability to reproduce by normal means; their species was dependent on a process of cloning and transferring the mind, although this caused a decay of the Asgard genome that eventually led to the species extinction. While the Asgard maintained a great fleet of ships with extensive capabilities, they were altogether not a militaristic race and strongly disapproved of using technology aggressively. For this reason, the beaming technology equipped on Tau'ri ships had many safeguards in place to prevent the transporters from beaming warheads aboard enemy ships (though this safeguard has since been removed).
When the Asgard realized that they were going to die and planned to commit mass suicide in order to prevent their technology from falling into the wrong hands, as it had with Ancient technology in the hands of the Goa'uld. They summoned the Odyssey to Orilla in order to give new upgrades to the ship as well as the Asgard computer core so that the Tau'ri would have access to all of their technology as their legacy and as the Asgard felt that the Tau'ri was the Fifth Great Race and was the only hope for peace. Among the upgrades was the Asgard plasma beam weapons, the first time a Tau'ri ship had been given Asgard weapons. These new weapons proved extremely effective against the most powerful shields, penetrating those of the Ori warships and Aurora-class battleships in just a few shots, destroying them. While it was shown in an alternate timeline that Wraith hive ships can also be destroyed in just a few shots, the Super-hive proved immune to the weapons due to its sheer mass, taking minimal damage even when two ships attacked it at the same time with the weapon. This hive ship was the only ship known to be nigh-immune to these Asgard weapons.
- Beaming technology
- Cloaking technology
- Cloning technology
- Computer core
- Consciousness transfer technology
- Control crystal interface
- Explosion suppression system
- Hand device
- Holographic technology
- Hyperdrive technology
- Invisibility device
- Ion guns
- Neutrino-ion generator
- Power core
- Replicator disruptor satellite
- Sensor technology
- Shield technology
- Shock spear
- Stasis pod
- Thor's Hammer
- Asgard technology on Wikipedia