Every good emulator accomplishes several goals. The fist, and most obvious one is the instant fun factor these old games are capable of producing. In an day and age of blockbuster games that have development budgets that were once reserved for movies, it’s refreshing to be able to reminiscent of times past with a couple levels of Zelda, Mario or PacMan.
Then, there’s a bit more serious goal that the emulators have. Let’s call it preservation. Many of us were born in the first era of personal computers and entertainment systems, and some of us have an attachment to the systems and games that we grew up with. Sadly, most of those are no longer in production.
Let’s take Nintendo Game & Watch system for example. This was a shortly lived and fairly unsuccessful piece of hardware from the Japanese gaming giant Nintendo. These devices first saw the light of day in early eighties, and by now, the time has taken it’s toll on them. Most of over forty million of Nintendo’s Game & Watch units that we’re produced were destroyed, or broken down due to age and use "DS emulator". They might still not be impossible to find, but even now, there’s a market for many of these exotic and lesser known consoles. It wont be long before they are so expensive that 90% of gamers and enthusiasts wont be able to afford them. Years after that, no one will be able to afford them at all – they will all be either gone for good or in a museum display.
When that point in time is reached, the only real way to experience those gems of games that were programmed to run on now extinct hardware will be emulation on modern hardware that the games weren’t built to run on in the first place. To accusative this, the emulators must be developed with maximum accuracy in mind, and doing that requires serious processing power.
Accurately emulating hardware from old consoles comes at a serious cost in CPU cycles and calculating power. There’s a rough rule that most developers and programmers who are working on emulators are aware of:
In order for an emulator to be two times as accurate, it must become approximately two times as slow. If you would to double that accuracy once more, you would get an emulator that’s four times slower.
It’s easy to see the problem. But there’s more – the rewards for this gain in emulation accuracy diminishes fairly quickly. Most players regard games to look “close enough” and feel “playable enough” at what is considered low to modest levels of emulation accuracy. This is why most emulators are trying to walk on the fine line between optimal compatibility and optimal performance. Most agree that this point, or a sweet spot of emulation is to be found at around 95 percent compatibility with the original hardware. Again, 100% would be ideal, but the required power just doesn’t make it worthwhile for most users.