Technical Limitation
Main Memory Disclaimer
Part of the main system memory may be used by the graphics system for graphics performance and therefore reduce the amount of main system memory available for other computing activities. The amount of main system memory allocated to support graphics may vary depending on the graphics system, applications utilized, system memory size and other factors.
For computers configured with 4 GB of system memory, this will only be visible on a 64-bit Operating System minus what has been allocated to the graphics system. The full system memory space for computing activities will be considerably less and will vary by model and system configuration.