Many of the emulators listed above have the ability to scan your entire device and find ROMs automatically. But you'll be enjoying your games faster if you tell the app where to look for them. All modern apps will support both internal and external storage. In our tests, we haven't noticed any performance difference between the internal storage on your device or an external microSD card. Furthermore, if you are planning on running multiple emulators for different consoles on your device, we recommend creating subfolders dedicated to each console.