Official System Requirements - Heroes 5

To play Heroes, you need either an NVIDIA or ATI graphics card with 64-128MB of memory (for optimal performance, 128-256MB is recommended). The processor should be at least 1.5GHz, and it's desirable to have 1GB or more of RAM, as XP consumes about 20% of the available memory, leaving less than you might want.

On a system with the specifications described above, Heroes of Might and Magic 5 will not only run but also provide you with a pleasant gaming experience.