GTA 5 from Epic Games - Preposterous quality

I was running a cracked version of Grand Theft Auto 5 (downloaded via uTorrent) before Epic Games decided to give it for free, so I got it for the Online experience. I recently installed it on my PC and my oh my, it is a disaster. The FPS is horrid, let alone textures and colours. My PC is considered a potato in the gaming world (i3 6100, 4GB RAM, GT 710 2GB), but I never faced so many hiccups whilst running the cracked version. I used to get steady 25-35 FPS with the cracked version, but I only get 15-20 FPS + Colours that are way too bright + Poor textures whilst running the original version. Why does this happen, and are there any solutions to this? (That doesn’t include upgrading hardware)