Here are the minimum and recommended system requirements to run Sid Meier's Civilization 4 smoothly and efficiently without any crash, freeze, slowness etc. on any computer;
Minimum System Requirements:
CPU: 1.2 GHz Intel Pentium 4 or AMD Athlon processor or equivalentRAM: 256 MB RAM (Windows 2000) / 512 MB RAM (Windows XP)GPU: DirectX 9.0c-compatible 64 MB video card with Hardware T&L support ( GeForce 2/Radeon 7500 or better)DirectX: DirectX® version 9.0c (included) or higherOS: Windows® 2000/XP with SP1 or higherHDD: 1.7 GB FreeSound Card: DirectX 9.0c-compatible sound card
Recommended System Requirements:
CPU: 1.8 GHz Intel Pentium 4 or AMD Athlon processor or equivalentRAM: 512 MB RAMGPU: 128 MB Video Card w/ DirectX 8 support (pixel & vertex shaders)DirectX: DirectX 9.0c-compatible sound cardOS: Windows® 2000/XP with SP1 or higherHDD: 1.7 GB FreeSound Card: DirectX® version 9.0c (included) or higher
Please also have a look at other posts under “System Requirements” category to view & check if your computer system is powerful enough to run other games like Sid Meier's Civilization 4 smoothly.