IQ by its own is not enough. A higher than average IQ is probably the result of a larger than average working memory, and maybe also some ability to make more "long-range" connections between concepts in the brain. That's raw processing power. But raw processing power isn't everything. You also need an otherwise healthy mind, the sustained motivation to accomplish great things and the ability to focus to dedicate enough time towards those goals.

For example if you read the biography of Von Neumann, it's remarkable that he was able to focus and work in the most noisy and distracting environments.