But three-reel slots with mechanical reels still have their following.
Truth be told, the games are more alike than different, with results driven by random number generators. But the difference in formats does affect the play experience. Whether on video or reels, games can have odds leading to the same payback percentage, but have a completely different feel.
Let’s take a look at some key areas:
Reels and Symbols
There’s a limitation inherent with mechanical reels: They must fit within the slot machine casing.
Ever since 1895 with the debut of Charles Fey’s Liberty Bell as the first three-reel slot, the most common configuration for slots with mechanical reels has been three reels. There are some with five mechanical reels, but the width of the reels and the size of the symbols must shrink dramatically to keep the package small enough to fit inside.
Additionally, the number of symbols per reel is limited by the reel size. At 20 symbols and 20 spaces per reel, the reels fit comfortably. If you try to expand to 40 symbols and 40 spaces, it starts to be a problem.
There are no such difficulties on video slots. Reels and symbols are virtual and many configurations are possible. Five reels are the most common configuration, but there are six- and seven reel games, and if a game needed a dozen reels to provide the desired game experience, there would be no worries about fitting within the casing.
Likewise, there can be as many symbols programmed per reel as the game designer needs. The symbols take up no real space, after all.
Most slots have one payline, connecting the center symbols across three reels. A few have three lines, one connecting the top symbols on each reel, one across the middle and one across the bottom.
Video slots usually have many more paylines. Today, 40 lines is a common number, and it’s not unusual to find 20, 30, 50 or even 100 lines.
Some of the difference is tradition. The first reel slots had one line, and that’s what players have become accustomed to.
Some is a limitation of having only three reels. If you were to make every path connecting three symbols across three reels a payline, you’d hit a maximum of 27 lines – 3 x 3 x 3. On a five-reel video slot with three symbols on each reel, that number is 3 to the fifth power, or 243. That corresonds to the 243 ways to win, or “Reel Power,” format you see on some video slots.
Payoff size vs. Payoff frequency
With only one payline (most of the time), three reel slots tend to pay off less often, but to pay more money per winning spin.
Nearly all payoffs on three-reel, one-line games are several times the size of your bet. On a common Double Diamond pay table, the smallest payoff for a three-coin bet is six coins for a single cherry, and the next smallest is 15 for two cherries or three mixed bars.
Look at that again. The smallest payoff is twice the size of you bet, and the next smallest is five times the size of your bet.
On a five-reel slot with 20 or more lines, it’s not at all unusual to get a payoff that’s smaller than your bet. On a 40-line slot, a bet of one coin per line might bring a payoff of 10 coins or fewer. Of course, there is the opportunity to win on more than one line at once, but many winning spins will lose money.
All those small wins add up to enough credits for extra spins to go for something bigger. Video slots also pay off much more often than reel slots. Single-line reel slots pay on only about 9 to 13 percent of spins, depending on the game. Some reel slots have paid on more than 50 percent of spins, and even the most volatile games pay on 20 percent or more.
With that difference in the frequency of winners, you can see the reason for the difference in payouts per win. With such a small percentage of winners on reel slots, each winner has to be bigger to wind up with the same overall payback percentage as a slot with more frequent but smaller wins.
Video slots are built around bonus events. The reels don’t have to stay on the screen. Programmers can give the game a bonus event where you get a totally different scene, such as hunting aliens, picking gift boxes or fishing on a pond, and let you make choices in a game within a game. They can build free spins into a game, or have a bonus wheel pop up on the screen, or use a combination of events with several different potential bonuses within the same game.
For most of their history, reel slots have not had bonus events. The entire game was winning or losing on the payline.
There are still reel slots like that today, but many now incorporate bonus events. Some put a bonus wheel on top of the machine. Some use free spins – easy enough to do on a reel format. Some even add a video screen in the top box or use clear glass in from of the reels that can transmit animation for pick-a-prize bonuses.
But it’s difficult to incorporate multiple bonuses to give reel slots the same entertainment texture as video slots. On reel slots, bonuses tend to feel like extras, while on video slots, bonuses often are the point of the game.
If it’s the top jackpot you’re after with that chance to win thousands of dollars or euros, your chances are better on a three-reel slot.
Video slots put much more of their payback in their frequent small wins and bonuses, while reel slots funnel their payouts during wins on the reels. A bigger percentage of a game’s overall payback comes from the top jackpot on reel slots than on video slots.
So it’s up to you: Do you love the slots for the entertainment of the bonuses, for the free spins and the games within a game, or are you a gambler who is willing to risk more frequent losing spins for the chance to win many times your bet on one spin? There are games for all tastes, and the choice is yours.