Let’s look at the facts.
Charr
They invented cannons (the Luxans only had a very crude type of bombard), guns, tanks, military-grade encryption, mortars, cars, airships, fans, gramophones, the printing press, turrets, flamethrowers, alchemical processes, and lots of other things which are now commonplace in Tyria.
Every prototype they create is pragmatic, functional, and thus able to be mass-produced.
And they are mass-produced, in their factory cities!
The charr mine all their own materials, using machines of their own construction, and manual labour. They’re truly self-sufficient in this regard.
The charr can process and purify most (or all) metals.
The charr use a scientific process of understanding, thus their creations don’t rely upon any kind of crutch (like… oh, say… magic).
The charr believe in cooperation which goes beyond politics. If you put three hundred charr in a hall, you’d end up with brilliant plans and fantastic ideas, all of which could be put to use.
The charr believe in only self-reliance and the worth of their fellows.
Conclusion: The charr are not only intelligent, but completely legitimate. Their intellect comes from actually doing things, rather than being all talk. Their real world equivalent would be the scientist who always gets results.
Asura
The asura have managed to invent gates and golems.
Almost every asura invention is a massive failure, and tends to either explode or go horribly awry.
The asura rely entirely upon incantations and handwavium. If this was taken away, they’d become helpless and vulnerable.
The asura cannot mass-produce, so they have to contract out to other races to build for them (see: the new gate complex in Lion’s Arch).
They have no ability to work with anything other than stone, and rely upon the charr for their metals (they send expeditions to the Black Citadel to try and figure out how the charr purify metals, but so far have had no luck reproducing it).
The asura have no true concept of proper scientific methods (only romanticised mad scientist nonsense), and merely use magic to ape scientific progress. Without magic, they’d be useless.
The asura have no concept of working together, and if you put three ausra in a room, you’d end up with one dead, one blind and dumb, and one swearing innocence.
The asura religion almost borders on scientology in how they’ve tried to actually turn science into a religion. And that’s what they believe in. This is what shows their lack of true intellect more than anything. If they had any idea of how proper science works, they wouldn’t be trying to turn it into a system of faith.
Conclusion: The asura are amateurs who dabble in forces that they have serious trouble even beginning to understand, forces which were already refined to perfection for them (by the human gods). Their real world equivalent would be the pseudo-intellectual script kiddie; the sort that tries to sound intelligent whilst only having the barest understanding of the words they’re using or things they’re tinkering with.