How more efficient would computers be if binary changed?

Binary is a number encoding scheme. You wouldn't be talking about binary if there were 3 possible digits. You'd be talking about trinary, or something like that. Computers used to use valves that would store values. Each valve would have a state depending on how much charge it contained. The problem with that was the valves lost charge and the values they were storing. People tried to think of ways to recharge the valves reliably for a while... but ultimately, this is why they started to use binary; If there's a charge it's a 1, otherwise it's a 0. It's more reliable.

Valves generate more noise and heat. They are a lot more expensive than transistors, but they're still used in audio. You're talking $5000 for a decent valve amplifier, where a $500 solid state amplifier might produce comparable sound. On the up-side, they do emit a very pretty light :)

In short, it's been done and I doubt we'll go back there. Valves may or may not work for audio, but they certainly do not work for computers.

they would decrees in effective because now the computer has to determine what state the voltage is at. it would then become an analog computer. all the programs we currently have would no longer work, binary is the best system for a computer to understand. it also makes being a programmer and engineer much easier to program build the equipment. you would have to change all the hardware in a computer and start all over. it would not be very effective...

Firstly it wouldn't be binary if you were able to add more than 2 states within a bit. In the old fashioned copper wired world, as others have said, it's much more resource intensive and harder to keep a steady and reliable hold on a state based on variable charger rather than the more simple and reliable charge or no charge method.

As computing evolves into more complex and powerful forms such as biological and fiber based, it can be better managed and reliable. Using the vastly large light spectrum as a coding method in determine the chemical and elemental make up of material has already been done for years, and something out of this could be used in creating a new base system for a fiber based computer, that is the circuit itself is made up of fiber optic technology rather than an electrical one. Biocomputers, which a few have already been created to demonstrate their potential are based off of the concept of using DNA and proteins to process, store, and compute data. They use a whole different system of states and base data constructs using amino acid sequences just like living organisms.

At this point, I really don't see a performance boast happening from it, or a need to move above a binary base as long as we can continue to expand the bandwidth (as in moving from 32bit to 64bit to 128bit).

you can not have semi on semi off, computers know only one thing - is it on or is it off, is there current flowing through a circuit or is there not.