Advanced Chipset Setup
Share Memory Auto Detection (Enabled)
Disable this item to set the Share Memory Size. And if the item is set to Auto,
Share Memory Size can be controlled according to the dram size. When the dram
size is less than 512 MB, Share Memory Size should be set to 64 MB. While
between 512 MB and 1 GB, it should be set to 128 MB. When more than 1 GB,
it should be set to 256 MB.
First the 'Share Memory Auto Detection' setting must be disabled.
After this is disabled the 'Share Memory Size' menu can be accessed.