I own a Lenovo laptop with an I5-5200U, Intel HD 5500 (Iris Pro, Broadwell-U GT2) and an R9 m375 4GB (AMD Tropo) and I play GTA V with these settings:
Resolution: 1280*768
4 units on distance scaling and 6 units on population density.
Texture and Shader Quality: Very High (which is highest)...