There are various surveys that show a correlation between intelligence and atheism. This doesn't, however, mean that embracing atheism will automatically make you more intelligent. Remember, correlation does not imply causation, and even if it did, it wouldn't show which is the cause and which is the effect.
Having a certain level of intelligence should make you naturally curious, eager to seek out knowledge. After exploring various ideas, you should eventually stumble upon an ideology that separates correct theories from incorrect ones: science. It's up to you whether you like science or not, but by its very definition, it's the only way to sort the correct ideas about how nature works from the incorrect ones. You can say that a particular scientific experiment wasn't carried out with enough scientific rigour, but if you say that science as a whole is wrong, you'll look very misinformed indeed.
Once you learn how to apply the scientific method to your examination of the world around you, and how to verify the scientific rigour of other people doing the same thing, you've essentially learnt how to discern what's true from what isn't. It's then only a very short step to discovering that all religions are incorrect in their provable statements, such as the efficacy of prayer or casting magic spells. More to the point, after looking at their claims objectively for a second, it soon becomes apparent that they are all batshit crazy.
The more you learn about astronomy, for instance, the more you realise how utterly insignificant we are. The more you learn about biology, the more you learn about where we came from and how we relate to all the other lifeforms on this planet. The more you learn about neurology, the more you learn about how consciousness itself, the sum total of our thoughts and feelings, our desires and dreams, arises from so many billion neurons.
None of this leaves much wiggle room for souls or afterlives, side effects of the naïve belief that we are somehow not really a part of -- and perhaps more important than -- this place we inhabit. In reality, we're just a tiny, insignificant part of a phenomenally large ongoing process, and it's testament to how beautiful the laws of the universe are that they've spawned not just lifeforms, but lifeforms that can contemplate their surroundings, themselves, and even the beautiful simplicity that brought them into existence in the first place.
Knowledge of biology in particular has a very strong correlation with atheism, for good reason. Once you start reading about how humans are evolving away from other apes, just as all lifeforms are constantly evolving away from their ancestors, in a very slow process that's a wonderful side effect of lifeforms eating each other and reproducing imperfectly, you realise this explanation of where we came from and why we became more intelligent than our distant cousins is simple, beautiful and complete -- and more to the point, proven true with a mountain of evidence -- with no need for any form of divine inspiration to explain our existence.
The more you learn about how the universe works, the more sense it makes, and the less places there are for magic to hide. Trying to work out when a god, magic or fate might have intervened during our gradual development, now that we actually know how we developed, is akin to trying to work out if the actual magic happens before or after the stage magician forces a card. Once you know how the trick is performed, there's simply no need to believe in magic any longer. Instead, we learn to appreciate the beauty of the trick, the cunning of the sleight of hand. Even more amazing is an inadvertent magic trick which doesn't even require a magician to perform it, happening as a mere side effect of the simple rules that govern everything.
So although atheism doesn't cure stupidity, intelligence does cure religion. More accurately, intelligence and knowledge should eventually render religion obsolete, for both the individual, and hopefully one day for society at large. We already know enough about the universe and our place in it to no longer have any excuse for believing in fairytales.