ARMSX2 v2.9 Brings Automatic Performance Tuning to Android PS2 Emulation

The update is available on GitHub and the Play Store. Its headline feature, Automatic Performance Tuning, makes several changes in the background to try to improve game speeds. According to the changelog, a new option watches for what is holding a game back and tries settings covering resolution, blending, texture download mode, the GS back thread and the emulated CPU’s clock. It keeps a change only when the game gets faster and remembers the change for that game. Android Authority reported that the feature is useful for users struggling to reach smooth or playable performance, but it cannot compensate for low-end hardware.

ARMSX2 v2.9 also recommends a custom GPU driver during first-time setup. On Snapdragon-powered devices with an Adreno 600 or Adreno 700 series GPU, the emulator prompts users to install the ARMSX2 Turnip driver. On devices with Mali graphics, it prompts users to install MaliSX2.

The update brings faster operation on the Retroid Pocket Duo dual-screen handheld, including performance improvements in games such as Shadow of the Colossus, God of War 2 and Black. Two additional performance features are included: the VU1 Ahead-of-Time Recompiler and the IOP Thread. The VU1 feature concerns the PS2’s Vector Unit 1, which handles much of the original console’s 3D mathematics. According to the changelog, ARMSX2 now recompiles the VU1 programs a game runs most into faster code on a background thread and remembers its plan for them, so they are fast from the start the next time the game is played. The IOP Thread option lets PS2 input/output settings such as controller, audio, disc reading and memory card run on their own thread instead of the main emulation thread, which translates into faster emulation on devices with at least four big CPU cores. Android Authority reported that Shadow of the Colossus runs up to 11% faster on the Retroid Pocket Duo with this setting enabled.

Other changes in v2.9 include file names in the library list, box art for games pinned to the home screen, a toggle to capture audio during screen recordings, and volume and mute controls in the in-game menu.