The 9250 will provide better performance, overall, than the integrated x200 GPU chipset. Especially when you consider that the x200 uses main memory for its memory. The 9250 will use its own on-board memory, thus freeing those resources for the system to use. Discrete GPUs almost always outperform integreated GPUs when they are comparable, as these ones are. Go with the 9250 for better performance.
True, but the x200 GPU is a crippled X1300, at best, and it draws on system resources directly, where the 9250 will not.
In all honesty, neither card is suitable for modern gaming given the limted capabilities of either solution.
If an AGP solution is required, an HD4650 AGP would be MUCH better. If a PCI-E solution is supportable, there are any number of better solutions. If this is a PCI-slot (not PCI-E) 9250, then the x200 will be more capable, but will still consume main memory, thus reducing overall system performance.
The true answer here is "it depends". Need to know more about the hardware, OS, and apps/games involved to make a good recommendation.