PCI Express System Architecture

Introduction to Power Budgeting

The primary goal of the PCI Express power budgeting capability is to allocate power for PCI Express hot plug devices, which can be added to the system during runtime. This capability ensures that the system can allocate the proper amount of power and cooling for these devices.

The specification states that “power budgeting capability is optional for PCI Express devices implemented in a form factor which does not require hot plug, or that are integrated on the system board.” None of the form factor specifications released at the time of this writing required support for hot plug and did not require the power budgeting capability. However, form factor specifications under development will require hot plug support ...