As listed on iRacing's site the minimum iRacing requirements for your iRacing PC build are as follows:
- Windows 7 64 Bit
- Intel Core i3, AMD Bulldozer CPU
- 8GB RAM
- Nvidia GeForce 2xx, AMD 5xxx
The listed componenents will obviousle be the bare minimum to run iRacing with reduced features and experience. Obviously if you want to run dirt, VR and multiple screen you will need to exceed these iRacing system requirements.