The challenge for the slot machine manufacturers has always been to devise the best balance of each of these key factors. It was easy for them to adjust reel configurations to balance out the Hit Frequency and Payback Percentage, but they were up against a brick wall when it came to offering the huge jackpots. They could only fit so many reels into a machine and so many symbols on each reel. The inherent problem with mechanical slot machines was the physical limitations.
In 1984 all of this changed when the ”Electronic Gaming Device Utilizing a Random Number Generator for Selecting the Reel Stop Positions” patent was purchased by IGT and the concept of “Virtual Reels” was put into practice.
You see, it doesn’t matter anymore whether you are looking at a slot machine that has physical reels inside of it that spin, or if you are playing one of the newer Video Slot Machines…they all work the same. As a matter of fact, the slot machines with physical reels that spin are in my opinion more deceptive than the Video Slot Machines. Using the Liberty Bell slot machine example with 10 symbols/stop points on each reel, your expectation would be that you have a 1 in 10 chance on any spin that a given symbol will hit the pay line for any reel. THIS IS NO LONGER TRUE.
Slot machines using the Virtual Reel technology have redefined the reel configurations using a computer program on a chip inside of the slot machine. So for example using the Liberty Bell machine, you may see 3 reels with 10 physical stop positions each, but now there is a computer program inside saying “No…each reel actually has a lot more stop positions, more than you can imagine, and although it has the same symbols you see on the physical reel, I’m not going to tell you how many of them I have on each reel”. Basically, you can no longer calculate the probability based on the physical layout of the reels because that no longer matters.