Forza Horizon 3 System Requirements

If you want to play Forza Horizon 3 without the lag you need Intel Core i5-3570 @ 3.40GHz / AMD Phenom II X4 975 processor and Nvidia GeForce GT 740 / Radeon R7 250X Graphics Card
You need the above Operating System or a superior one to run this game with no technical problems. The most basic installation will require at least 55 GB of free disk space on your hard drive. You need 8 GB RAM of Free RAM to run this game with no technical problems and also You need  DirectX 11 version or later to run this game with no technical problems.

Processor:  6th Gen Intel  Core i5, AMD Quad-Core Ryzen 5
RAM: 8 GB
Operating System: Windows 10 (64-bit version)
Graphics Card: NVIDIA GeForce GTX 1050   or AMD Radeon Vega 8 Graphic Processor
Graphic Video Ram: 2 GB
Game Size: Between 40 to 60 GB

Processor:  7th Gen Intel  Core i7 , AMD Quad-Core Ryzen 5
RAM: 16 GB
Operating System: Windows 10 (64 bit version)
Graphics Card: NVIDIA GeForce GTX 770  or AMD Radeon Vega 8 Graphic Processor
Graphic Video Ram: 2 GB
Game Size: Between 40 to 60 GB

Forza Horizon 3 System Requirements (Minimum)
Processor: Intel i3-4170 3.7Ghz OR Intel i5 750   2.67Ghz or AMD Phenom II X4 975
RAM: 8 GB
Operating System: Windows 10 version 15063.0 or higher
Graphics Card: NVidia 650TI OR NVidia GT 740 OR AMD R7 250x

Graphics Video RAM: 2 GB
Game Size: between  40 to 60 GB

Forza Horizon 3 Recommended Requirements
Processor: Intel i7-3820 @ 3.6Ghz
RAM: 12 GB
Operating System: Windows 10 version 15063.0 or higher
Graphics Card: NVidia GTX 970 OR NVidia GTX 1060 3GB OR AMD R9 290x OR AMD RX 470
Graphics Video RAM: 4 GB
Game Size: between 40 to 60 GB