PC very stuttery/laggy on horizon 3

used that program and it said during gaming it used 100% cpu usage almost constantly on all 4 cores, and the GPU spikes twice to almost 100% b ut it was literally a spike for a split second during the time I was on other than that it was OK. RAM usage was at 7816 MB max, which I guess would be 7.816 GB which being 8GB is my max…

plus game runs relatively smoothly except for when I am like above 100 MPH or in a busy area like the city… just going slow in the desert my framerate is OK

if I had to take a stab at it, I need more ram? does any ram work? what do I do about my CPU do you guys have any suggestions? should I try lowering ALL graphics to minimum? I don’t know if that would matter because it seems the GPU is holding its own, which means graphics aren’t the problem?

thanks alot