Sleeping Dogs is very well optimized. Even a modest laptop with integrated graphics can run it at 720p. You can find the Definitive Edition on Steam, GOG, or Humble Bundle for as low as $3–$5 during sales.
When searching for files labeled "Sleeping Dogs PPSSPP," you are entering a high-risk zone for malware.
This is the best modern solution:
This gives you the full game with good graphics and proper controls, especially if you pair a controller (like a Razer Kishi or Backbone).