The system should be tuned such that the fastest generally available computer would not be powerful enough to emulate the slowest computer that would be allowed to run the game. Depending on the pace of progress of computer technology and the lifespan of the game, it might eventually be necessary to change these requirements and force the users of the slowest computers to upgrade their hardware if they want to continue playing the game. While this would be frustrating for these players, I don't have a problem with it as long as there is a contract between the players and the game company that both agree to and are bound by - it would be part of the cost of playing without cheaters. Though I would hope that independent servers without these restrictions would also be available if there is demand for them.