An IBM computer crushed two human champions Tuesday in the second round of a man vs. machine showdown on the popular US television game show "Jeopardy!"

Most of the banter and gentle humor that usually pepper the popular quiz show was gone as the supercomputer dominated the game by beating his human opponents to the buzzer again and again.

Ken Jennings -- who holds the "Jeopardy!" record of 74 straight wins -- shook his buzzer in silent frustration as the computer's artificial voice answered the first dozen challenges without pause, getting all but one right.

"Watson" - named after Thomas Watson, the founder of the US technology giant -- receives the clues electronically by text message at the same time as they are revealed to the human contestants.

The first player to hit the buzzer gets to answer the question. The others only get a chance if the first player gets the answer wrong.

Watson, which is not connected to the Internet, plays the game by crunching through multiple algorithms at dizzying speed and attaching a percentage score to what it believes is the correct response.

It beat Jennings and Brad Rutter -- who won a record $3.25 million on the show -- to the buzzer on 24 of 30 questions.

Five-time "Jeopardy!" champion Jeffrey Spoeri sympathized with Jennings and Rutter, and said the computer's speed to the buzzer seemed like an unfair advantage.

"I gotta root for the humans," said Spoeri, who won 105,000 dollars on the show in November 2006.

But he was deeply impressed with the computer's skills.

"The actual game play was just amazing, that it would know the answers and discern which one is the correct one," Spoeri told AFP after viewing the first show.

"It's a terrific experiment."

Watson, which has been under development at IBM Research labs in New York since 2006, is the latest machine developed by IBM to challenge mankind.

In 1997, an IBM computer named "Deep Blue" defeated world chess champion Garry Kasparov in a six-game match.

"Jeopardy!", which first aired on US television in 1964, tests a player's knowledge in a range of categories, from geography to politics to history to sports and entertainment.

A dollar amount is attached to each question and the player with the most money at the end of the game is the winner. Players have money deducted for wrong answers.

In a twist on traditional game play, contestant