I looked it up, and the minimum GPUs named go back to 2007, so six years old now. PC System Requirements
Minimum:
OS: Windows XP Service Pack 3
CPU: Dual Core 2GHz Intel or 2.8GHz AMD
Memory: 2GB
Graphics: ATI Radeon X1600 or NVIDIA GeForce 7600 or better (512MB graphics memory or more. Shader Model 3.0 needs to be supported). Minimum supported resolutions 1280×720 and 1024×768.
DirectX: 9.0c
Disk Space: 1GB
The only thing somewhat "steep" in terms of year 2007 is the VRAM total of 512 MBs.
Kiwi