You may see some articles or tips about using the Intel HAXM, BlueStacks, Genymotion, Android-x86 or some other high performance Android emulator.
Most Android developers I talk to develop on actual hardware, but sometimes you need the emulator, and when you are using it you need it to run faster. This means the iOS Simulator is typically faster than actual hardware, and the Android Emulator is slower than actual hardware. The main reason is because it is emulating the ARM CPU & GPU, unlike the iOS Simulator, which runs x86 code instead of the ARM code that runs on the actual hardware.