What are the odds of Quads over Quads?

What are the odds of Quads over Quads?

preflop, on the flop, turn or river? if one has quads and the other a set, then that is only 1 out... so it would be less than 5%

Used this for my reference...
Bad-Beat Jackpots: The Basics

Odds are 1 in 100,000, when a full house is on the board, one player has pair in his hand and the pair is on the board for the first quad and the other player has the fourth card that matches the 3 matching cards on the board for the 2nd quad.

If both player have pocket pairs, the chances are one in 250,000.

Here is quads over quads in action...
http://www.youtube.com/watch?v=EKh0_rQhCpY

yeah i seen it a few times , never seen a straight flush beaten by a royal tho

Great video ....never seen that before.......I once got beat with a full house kings over aces to a full house aces over kings and thought that was bad beat but this takes the cake.