SimCity 4, released in 2003, is a city-building simulation game that focuses on intricate city planning and management, with a strong emphasis on urban development and infrastructure. It offers a more detailed and complex gameplay experience, allowing players to control various aspects of city management, such as zoning, transportation, and utilities. On the other hand, SimCity 2013, released in 2013, is a reboot of the franchise with updated graphics and a multiplayer mode. It focuses more on the social and interactive aspects of city-building, allowing players to collaborate and compete with other players in a shared online world. However, it received criticism for its smaller city sizes and always-online requirement. In summary, SimCity 4 is known for its depth and complexity in city management, while SimCity 2013 emphasizes multiplayer and social interaction. **

SimCity uses a single-threaded simulation engine that relies heavily on the CPU for processing. The game does not have a specific processor requirement, but it benefits from a fast and powerful CPU to handle the complex simulation calculations and AI behaviors. Players may experience better performance with a multi-core processor, as it can distribute the workload more efficiently. **

In SimCity, you can buy oil by using the Trade Depot or Trade Port. First, you need to have a city with a specialization in oil production. Once you have oil available for export, you can set up a trade deal in the Trade Depot or Trade Port to sell your oil to other cities. You can also import oil from other cities by setting up a trade deal to purchase it. Keep in mind that having a good transportation network and a strong economy will help facilitate the buying and selling of oil in your city. **

The SimCity server may not be accessible due to a variety of reasons, such as maintenance, technical issues, or high traffic. Maintenance could be taking place to improve the server's performance or to implement updates. Technical issues, such as server crashes or software bugs, could also be causing the server to be inaccessible. Additionally, high traffic from a large number of players trying to access the server at the same time could overwhelm the system and make it inaccessible. **

In SimCity, players can sell materials by using the Trade Depot or Trade Port. They can set up storage lots to store excess materials and then put them up for sale in the global market. Players can also set the price for the materials they want to sell and wait for other cities in the region to purchase them. Additionally, players can establish trade agreements with other cities in the region to buy and sell materials directly with them. **

Yes, in SimCity, players can expand their city by adding new zones for residential, commercial, and industrial development. They can also build new roads, public transportation systems, and utilities to support the growing population. Additionally, players can unlock new buildings and landmarks as their city grows, allowing for further expansion and customization. Overall, SimCity provides players with the tools and options to continually expand and improve their virtual city. **

You can earn SimCash in SimCity by completing various in-game tasks and challenges, such as upgrading buildings, completing city achievements, and participating in special events. You can also earn SimCash by watching video ads, completing offers from the in-game store, and by purchasing it with real money. Additionally, you can earn SimCash by reaching higher levels and progressing through the game. **

I'm sorry, but I cannot provide specific product keys for software as it may violate copyright laws and terms of service. I recommend purchasing the game from a legitimate retailer to obtain a valid product key. **