For a long time, the most common complaints about the Android emulator were its slow startup and operational speeds. Using the Intel Atom x86 system image helped a bit, but not much. However, last year, Intel released the Intel Hardware Accelerated Execution Manager (HAXM), which completely improved the situation. Previously, it took several minutes from the Android boot animation to reach the screen lock, but now it takes just 10 seconds!
Installing HAXM
First, ensure your CPU supports VT, which most CPUs nowadays do. Then, go to the Extras section in the Android SDK Manager and install the Intel x86 Emulator Accelerator (HAXM). However, this installation step actually only downloads the package; you need to complete the installation by finding it in the SDK Path. For example, on a Mac, it would be downloaded to SDK Path /extras/intel/Hardware_Accelerated_Execution_Manager. You would then open the IntelHAXM.dmg and run the pkg inside to finish the installation.
After running the Emulator, if successful, you will see in the Console: Emulator] HAX is working and emulator runs in fast virt mode. If you want to see how fast the Android emulator runs on a MacBook Air, you can watch the following video.