The thing is, it worked fine the first day I installed it, I even did a stress test by creating maximum police and gang presence as well as adding my own gang into the mix, there was no performance drop. I have also lowered the settings to medium despite having played the game on Ultra till now, I also run various mods from games that require more computing power than this one. Power options are on high performance. So my only thought is mod conflict which shouldn't be possible due to it being a compilation. In other words, I have run out of ideas. I will try installing it again.