If you can remove opening preparation (and all preparation) I think it probably is. Calculating moves is a good measure of working memory and is an important aspect of intelligence. There are certainly other things that are important, like creativity, but anyways, intelligence is probably not a specific enough word for this to be meaningful. But as an example, I think I'm intelligent enough in a lot of ways but my ability to calculate far ahead is held back by my mediocre working memory.