Here are the Bus Simulator 21 System Requirements (Minimum)
CPU: Intel Core i3-2120 / AMD Phenom II X4 830 or equivalent
RAM: 8 GB
VIDEO CARD: NVIDIA GeForce GTX 760 (2GB VRAM) / AMD Radeon R9 280 (2GB VRAM) or higher
DEDICATED VIDEO RAM: 2048 MB
PIXEL SHADER: 5.0
VERTEX SHADER: 5.0
OS: Windows 10 64-Bit
FREE DISK SPACE: 18 GB

Bus Simulator 21 Recommended Requirements
CPU: Intel Core i5-4440 / AMD FC-8140 or equivalent
RAM: 8 GB
VIDEO CARD: NVIDIA GeForce GTX 1070 (8GB VRAM) / AMD Radeon RX Vega 56 (8GB VRAM) or higher
DEDICATED VIDEO RAM: 8192 MB
PIXEL SHADER: 5.1
VERTEX SHADER: 5.1
OS: Windows 10 64-Bit
FREE DISK SPACE: 18 GB