Genesis Plus GX vs Mega-Pi

Genesis Plus GX is a free, open-source emulator for Sega's 8-bit and 16-bit systems, including SG-1000, Mark-III, Master System, Game Gear, Genesis/Mega Drive, and Sega/Mega CD. It supports backward-compatibility modes and describes its CPU, video, and sound emulation as highly accurate, with cycle-accurate CPU and sound synchronization. The emulator reads raw and interleaved ROMs, as well as CUE+BIN, ISO+WAV, and ISO+OGG CD images. Emulated peripherals include 2-, 3-, and 6-button pads, multitaps, the Sega Mouse, and light guns; supported cartridge hardware includes SVP DSP, EEPROMs, Game Genie, Action Replay, and Lock-On. Standalone builds are available for GameCube and Wii, and the project lists access through frontends such as RetroArch, BizHawk, and OpenEmu. It describes compatibility with released software for its supported systems, while noting that it cannot test every game from start to finish. Some Master System games depend on particular hardware or VDP modes. The multi-platform core source is under a non-commercial license.

Mega-Pi is a free, bare-metal Sega Mega Drive/Genesis emulator for Raspberry Pi hardware. It targets Raspberry Pi 3 and 4 and runs without an operating system such as Linux, which the project associates with near-instant boot and very low input latency. The emulator uses the Picodrive core and Circle bare-metal C++ framework, assigning orchestration, video, audio, and input work across four ARM cores. It scans .bin, .md, and .gen Genesis or Mega Drive files, plus Sega CD/Mega CD .cue files with .bin tracks and compressed .chd files. Sega CD emulation includes the Sub-CPU, PCM audio, CD audio, and rotation/scaling graphics hardware. Video uses 2× integer nearest-neighbor scaling to 640×480, with 44.1 kHz stereo through the Pi PWM sound engine. USB gamepads and keyboards are supported, and save states reside on the SD card. Running it requires a FAT32 card, boot files, a kernel image, game files, and USB input devices; Sega CD also needs regional BIOS files.