Size Overhead

1. Runtime memory overhead (visible to OS) : The size overhead of the runtime PE image is the same as the overhead of the SMM PE image. If a platform has n runtime images, the average amount overhead is 6K * n.

2. Boot time memory overhead (invisible to OS) : The size of the overhead for the boot time PE image is the same as the overhead of the SMM PE image. If a platform has n boot time images, the average overhead is 6K * n.

If the NX protection for data is enabled, the size of the page table is increased because we need set fine granularity page level protection.

The size overhead of the boot time page table is also same as for the SMM static page table. Please refer to the SMM section for the size calculation based upon the 1G paging capability and max supported address bit.