Frames per second
There are two kinds of "frames per second".
The first is the virtual FPS. If this is running at 60/60 then the emulator is running at full speed. The second is the real internal FPS, which is whatever the game actually ran at on real hardware. Most consoles use the following internal FPS based on region:
With the move to 3D, however, it took much more CPU power to run games at 60FPS. Most early 3D games run at 30FPS. Some run at even lower frame rates. The Legend of Zelda: Ocarina of Time, for instance, runs at 20FPS in NTSC regions, or 17 FPS in PAL regions. Star Fox runs below that.
If you are experiencing a slowdown, it may be that the emulation is too intense for your system. When this happens, both the video and the sound experience slowdown. To counteract this, you can enable speed hacks, use a less intensive emulator/settings or get new hardware. However, the slowdown may be part of the original game and will be emulated. As such there is nothing that can be really done, short of reprogramming the game itself or emulating an overclock. When this slowdown occurs, the video will slow down but the audio will often continue at full speed.
- Main article: Overclocking
A way to counter real internal slowdown is to overclock the CPU of the emulated system. This, of course, requires a faster CPU to run the emulator. It may result in a smoother frame rate or unintended effects such as speeding up the entire game. It is very game and system dependent. Emulators that support this:
Using speed hacks can affect both types of FPS in emulators. Most of these are used to alter emulation, sacrificing accuracy for speed to help achieve 60/60FPS. Some speed hacks, however, can lower the internal FPS to raise the emulator's FPS; an example of this is in PCSX2, known as EE cycle stealing, which reduces the clock speed of the virtual CPU used, the Emotion Engine.
There are a few game hacks that optimize game code in order to remove possible instances of in-game slowdown. There also exist a few speed hacks that increase a game's internal frame rate. They only function properly in emulators with overclocked hardware.
60 FPS Cheat Codes
- Main article: 60 FPS Cheat Codes
These are speed hacks in the form of cheat codes affecting the game's internal FPS for games running at 30 FPS to get them to play at 60 FPS. However, these are often game-specific and very prone to bugs considering many of the games weren't made with 60 FPS in mind. Notably, the walking speed and animations might play at double speed, which can cause some gameplay problems like for example, making a mission impossible to beat in Metal Gear Solid: Peace Walker because the enemies are too fast.