Portable mobile computing and communication applications demand low-power and low-energy with high performance. These competing demands drive SoC development. Especially, 3D graphics-intensive applications are predicted to become widely available on a variety of portable mobile devices ranging from laptops to PDAs to mobile phones. Such 3D graphics coprocessors were originally developed for home computers and game consoles, which use steady power supplies. But a portable mobile device has a limited battery life, which needs to be prolonged as much as possible. Consequently, low power design is the most important segment in order to become competitively portable mobile consumer electronics. We are developing a high-performance, low-power, 3D-graphics SoC to meet such requirements. This paper introduces our developing energy-awared mobile 3D graphics SoC and its real-time performance/energy monitoring and control.