Here is the honest truth. The S3 originally ran on 1GB of RAM. If you run the emulator on a modern PC (16GB RAM, SSD), the phone will feel unrealistically fast .
Unlike Apple’s tightly controlled iOS simulator, the Android emulator (based on QEMU) is a full system emulator. The S3 emulator was a specific skin and system image atop this. To understand its function, one must dissect its layers: Samsung S3 Emulator