128 MB VRAM, Pixel Shader 2.0b (ATI Radeon X800 / NVIDIA GeForce 7600) 8 GB available space DirectX Version 9.0c Why Choose Official Sources? Sneaky_Koala :: Review for Portal 2 - Steam Community

"Overwhelmingly Positive" (98% of 169,705 reviews) PC System Requirements

Portal 2 is highly optimized and can run on most modern and even older computers. Minimum Requirements Windows 7 / Vista / XP Processor 3.0 GHz P4, Dual Core 2.0 or AMD64X2 Memory Graphics