Forza Horizon 3 Unplayable on PC?

First off I dont have the best PC. Im in the middle of upgrading. However the performance this game gives me is beyond excuses. I play witcher 3 on medium settings at 1080p and I get well over 30 fps I average about 45. I downloaded the FH3 demo to see how it would run before buying the game itself. The beginning cutscenes were beautiful and I got very excited, all until The gameplay began.
WOW.
The game automatically had me at the lowest settings, and way below even 720p and it still ran like [Mod Edit - Abbreviated profanity, profanity and profanity that is disguised but still alludes to the words are not permitted - D] less than 15 fps. I decided to tune it down to the lowest resolution possible, no change. Just for fun I put it up to medium @1080p and remarkably NO CHANGE, some parts even ran a bit smoother. I am dumbfounded and dissapointed because I never had an xbox and was really excited to play this game. Any one else had the same issues and managed to fix it? is It just the demo? please someone help, heres my rig below

AMD FX-6300
Nvidia GTX 750 TI SC
Asus 970 gaming motherboard
8gb 1860 ghz ram
750W 80 plus power supply.
1 TB segate hard drive
120 GB SSD.