"We have two different projects that are at least vaguely in the works on the iPhone," said Carmack.
"Pure graphics wise, [the iPhone is] about equivalent to a Dreamcast, but if you were to compare it to a console, it's pretty close to a previous generation console."
"While the graphics aren't that high up, you've got a lot more RAM," he added, adding that RAM is where developers typically run into technical problems.
Carmack also noted that his relationship with Apple can be rocky.
"It's a rollercoaster ride with Apple always. They make nice when they want me to come make a keynote there," he said, adding that when he speaks honestly about the company, he often makes their "shit list."