OpenTTD is an open source simulation game based upon the popular Microprose game "Transport Tycoon Deluxe", written by Chris Sawyer. It attempts to mimic the original game as closely as possible while extending it with new features.
OpenTTD will require Radeon HD 6550D graphics card with a Celeron E1200 Dual-Core 1.6GHz or Athlon 64 X2 Dual Core 4000+ processor to reach the recommended specs, achieving high graphics setting on 1080p. System memory required for OpenTTD is 2 GB performance memory. Don't try and play OpenTTD without 1 GB, which helps get the 30FPS Another thing to consider is the DirectX capability of your GPU. OpenTTD needs a GPU capable of running DirectX 9. Recommended needs around a 10 year old PC to run.