GTA IV on Lenovo IdeaPad G580, Intel® CoreTM i3-2348M 2.30GHz, 4GB ram, nVidia GeForce 635M 2GB - - - - - - - - - - FPS medium settings: ~27-35 FPS high settings: ~20-30 FPS with fraps: ~20-23 - - - - - - - - - - If you have lag on GTA IV try this steps: