Unfortunately it will probably be way smarter than the smartest humans in no time... I just hope my death is painless when I'm conscripted to fight in the water wars after the US aqueducts are depleted
Throughout human history, essentially everyone who has predicted an upper limit for the development of any given technology has been completely wrong. The only people who have been correct are the ones who predicted technology accelerating to unimaginable heights at unimaginable speed.
Guessing an upper limit on AI is like guessing an upper limit on the stock market. Surely a limit exists, but only a fool would think they can call it.