One of the most direct methods for an agent to increase its computing power (does this translate to an increase in intelligence, even logarithmically?) is to increase the size of its brain. This doesn't have an inherent upper limit, only ones caused by running out of matter and things like that, which I consider uninteresting.
To follow up on what olalonde said, there are problems that appear to get extraordinarily difficult as the number of inputs increases. Wikipedia suggests that the know best solutions to the traveling salesman problem is on the order of O(2^n), where n is the number of inputs. Saying that adding computational ability resolves these issues for actual AGI implies either:
1) AGI trying to FOOM won't need to solve problems as complicated as traveling salesman type problems, or
2) AGI trying to FOOM will be able to add processing power at a rate reasonably near O(...
I was very interested in the discussions and opinions that grew out of the last time this was played, but find digging through 800+ comments for a new game to start on the same thread annoying. I also don't want this game ruined by a potential sock puppet (whom ever it may be). So here's a non-sockpuppetiered Irrationality Game, if there's still interest. If there isn't, downvote to oblivion!
The original rules:
Enjoy!