Asgard Tech vs. Ancient Tech

[webxro]

the thing is that is that the asgard tech increase efficiency if you increase power , the ancients have the same power but at a better energetic demand

[Rise Of The Phoenix]

Efficiency never changes, not really since the technology in question has a set limit e.g: it's materials never change.
It's just that when you pump more power into a device you end up get more for the amount of energy you put in compared to say Goauld shields (maybe not sure if that's a canon fact or not, but it would seem likely since the Asgard were alot more advanced and older than the Goauld).

We don't know whether the Asgard had tech that was more efficient than the Ancient's, it's possible that if they couldn't make better power devices than the Ancients then they worked at getting more out of things like Hyperdrives, so used less power to equal what say Ancient drives could do, maybe or maybe not.