Jeopardy! and IBM tried to ensure that both humans and machines had equivalent interfaces to the game. For example, they both had to press down on the same physical buzzer. IBM had to develop a mechanical device that grips and physically pushes the button. Any given player however has different strengths and weakness relative to his/her/its competitors. Ken had a fast hand relative to his competitors and dominated many games because he had the right combination of language understanding, knowledge, confidence, strategy and speed. Everyone knows you need ALL these elements to be a Jeopardy! champion.
Both machine and human got the same clues at the same time -- they read differently, they think differently, they play differently, they buzz differently but no player had an unfair advantage over the other in terms of how they interfaced with the game. If anything the human players could hear the clue being read and could anticipate when the buzzer would enable. This allowed them the ability to buzz in almost instantly and considerably faster than Watson's fastest buzz. By timing the buzz just right like this, humans could beat Watson's fastest reaction. At the same time, one of Watson's strength was its consistently fast buzz -- only effective of course if it could understand the question in time, compute the answer and confidence and decide to buzz in before it was too late.
The clues are in English -- Brad and Ken's native language; not Watson's. Watson analyzes the clue in natural language to understand what the clue is asking for. Once it has done that, it must sift through the equivalent of one million books to calculate an accurate response in 2-3 seconds and determine if it's confident enough to buzz in, because in Jeopardy! you lose money if you buzz in and respond incorrectly. This is a huge challenge, especially because humans tend to know what they know and know what they don't know. Watson has to do thousands of calculations before it knows what it knows and what it doesn't. The calculating of confidence based on evidence is a new technological capability that is going to be very significant in helping people in business and their personal lives, as it means a computer will be able to not only provide humans with suggested answers, but also provide an explanation of where the answers came from and why they seem correct.
Watson contains state-of-the-art parallel processing capabilities that allow it to run multiple hypotheses – around one million calculations – at the same time. Watson is running on 2,880 processor cores simultaneously, while your laptop likely contains four cores, of which perhaps two are used concurrently. Processing natural language is scientifically very difficult because there are many different ways the same information can be expressed. That means that Watson has to look at the data from scores of perspectives and combine and contrast the results. The parallel processing power provided by IBM Power 750 systems allows Watson to do thousands of analytical tasks simultaneously to come up with the best answer in under three seconds.