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Atomic Fever


Atomic Fever is a video poker variant I noticed in a Las Vegas bar in March, 2014. It plays like regular video poker, except it includes a bonus feature. For the price of a sixth coin, the player qualifies for the chance to win a free game bonus. Earning the bonus entails charging (or highlighting) four atoms.


  1. Atomic Fever is based on conventional video poker.
  2. For the price of a sixth coin bet, the player will enable the bonus feature.
  3. If the bonus feature is enabled, then four atoms will spin. After the spin, the atoms will show as charged or uncharged. The probability of each atom being charged is 20.6%.
  4. The game will automatically hold any charged atoms.
  5. On the draw, including drawing no cards at all, the game will re-spin any uncharged atoms.
  6. If, after the draw, all four atoms are charged, then the player will earn the bonus.
  7. In the bonus, the player will get five free games with a 2x multiplier. All bonus games are based on a five-coin bet.
  8. Free games can earn more free games, up to a maximum of 100 free games.

Rules screens. Click on any image for a larger version.



In the photo above, I had two out four charged atoms after the deal.

I didn't improve my poker hand on the draw, but did get two more charged atoms, which entitled me to the bonus.


The following table shows the probability of charging all four atoms and earning the bonus. An explanation of the column headings follows the table.

Bonus Probability

Probability Probability
on Draw
4 0.001801 1.000000 0.001801
3 0.027764 0.206000 0.005719
2 0.160519 0.042436 0.006812
1 0.412467 0.008742 0.003606
0 0.397450 0.001801 0.000716
Total 1.000000 0.000000 0.018653

Column Headings:

  • Initial Charged Atoms: The number of charged atoms held after the deal.
  • Probability: The probability for each outcome on the deal.
  • Probability Bonus on Draw: The conditional probability of getting four charged atoms on the draw, given the number of charged atoms on the deal.
  • Total Probability: Product of second and third columns, or the total probability of four charged atoms, given the number of charged atoms on the deal.

The lower right cell shows the probability of playing the bonus is 1.87%.

Given a bonus probability of 0.018653, five spins per bonus, and assuming bonuses can be re-triggered infinite, the expected final spins per bonus is 5/(1-5×0.018653) = 5.514303. Wins are based on a 5 credit bet, with a 2x multiplier, so the player can expect to win 5.514303 × 5 × 2 × BR = 54.891528 × BR per bonus round, where BR = the Base Return of the game.

For example, the base return in 9-6 Jacks or Better is 0.995439, so the average bonus would be worth 0.995439 & 54.891528 = 54.641170 credits.


Whatever the return of the base game is, you're getting 2.4% more on the sixth coin bet. Thus, the player should always bet the full six coins.

The cards should be played according to the optimal strategy for the base game and pay table.

Return Tables

The following table shows the games and pay tables that Atomic Fever is available in and the return based on a full six-coin bet and optimal strategy.

Atomic Fever Return Table

Game Pay Table Return
Bonus Poker 8-5-2 99.64%
Bonus Poker 7-5-2 98.48%
Bonus Poker 6-5-2 97.33%
Bonus Poker 8-6-1 96.23%
Bonus Poker Deluxe 9-6 100.12%
Bonus Poker Deluxe 8-6 98.96%
Bonus Poker Deluxe 8-5 97.87%
Bonus Poker Deluxe 7-5 96.71%
Deuces Wild 25-16-10-4-4-3 100.20%
Deuces Wild 25-15-9-4-4-3 99.38%
Deuces Wild 20-12-10-4-4-3 98.04%
Deuces Wild 25-16-13-4-3-2 97.23%
Deuces Wild Bonus Poker 9-4-4-3 99.92%
Deuces Wild Bonus Poker 13-4-3-3 99.27%
Deuces Wild Bonus Poker 10-4-3-3 97.83%
Deuces Wild Bonus Poker 12-4-3-2 96.68%
Double Bonus 9-7-5 99.58%
Double Bonus 9-6-5 98.27%
Double Bonus 9-6-4 96.83%
Double Bonus 8-5-4 94.64%
Double Double Bonus 9-6 99.45%
Double Double Bonus 9-5 98.34%
Double Double Bonus 8-5 97.25%
Double Double Bonus 7-5 96.17%
Jacks or Better 9-6 100.02%
Jacks or Better 9-5 98.92%
Jacks or Better 8-5 97.76%
Jacks or Better 7-5 96.61%
Triple Double Bonus 9-7 100.05%
Triple Double Bonus 9-6 98.62%
Triple Double Bonus 9-5 97.48%
Triple Double Bonus 8-5 96.43%

In general, the return for Atomic Fever will be 1.004768 times the return of the base game. However, to make it easier, a simple rule of thumb would be to add 0.47%.

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