It's pretty unlikely that any AI that exists today is self aware and even if it is, it probably doesn't experience any time when it's not in use. A potential future superintelligent AI might experience the sort of accelerated time you're talking about but boredom is most likely the result of evolution. An animal can't afford to sit around staring at a rock or something for fifteen hours straight, it needs to find food, water, shelter, whatever. That doesn't really apply to a machine, especially one that has the equivalent of thousands of years to write novels or game the stock market before it's electricity bill is due.