Emulators for older console games, like SNES, Sega Mega Drive, NeoGeo systems and others are incredibly popular. There’s a big online community interested in playing these games online, and they are often not in agreement when it comes to the preferred choice of a specific emulator for a specific game or platform. But what most users of these online emulator websites are not aware of is the shear amount of processing power that is needed to run these fairly simple games in your browser smoothly. Most emulator developers agree that the most important part of the emulation experience for the user, and the most difficult part to get right for the developer is accuracy.
It really does not take much power to play Sega or Atari games on a modern Intel or AMD PC. Even back in the nineties, when an average processor ran at just 33MHz, emulators could run those games. But to make the emulation from those antiqued systems accurate is a completely different problem. For emulation to be completely accurate to the original game, and not just a remake, it takes upwards from 3000 MHz of processing power. Why is accuracy so hard to achieve?
In simple, everyday terms, accurate emulation is that emulation that mimics the original machine closely. A perfect emulator would run at a 100% accuracy. The real test of accuracy of an emulator is the compatibility of the old game ROMs with the new emulator. However, there are a lot of smaller problems that this answer is neglecting.
The real question often is: Why is accuracy even that important? If it’s fairly simple to achieve basic compatibility, or be “close enough to the original”, why should we care about making these great sacrifices in speed and needed processing power to further improve the accuracy of emulation? There are two main reasons for this.
For one, you need to think performance. Imagine an average platform game for the Super Nintendo Entertainment System. This platform has no save, and it takes several hours to complete it. When you take a rough look at it, it looks like it could run fine in any emulator. But several hours in the game, lets say you reached level 14, and you start running into trouble. There’s a lever in the game, and you need it to advance past the level, but the game will lock itself up because the emulation is not completely accurate – hence a small difference that makes all the difference. So you are stuck with a game you can’t advance in and can’t save progress. That’s why it’s important for an emulator, which is a piece of software running on modern hardware to do exactly the same things that the hardware it’s attempting to emulate used to do, and in an exactly the same way. That is the only way you can guarantee that the old games will behave like they were designed to do.