Here the GMABooster comes!

It allows a user, not a manufacturer to choose the desired GMA speed. It combines a sophisticated assembler-level technology and the user-friendly graphic user interface, offering You to near double the GMA core perfomance without even a need to restart a computer. GMABooster may be considered as a safe, free, "software-level" GPU core upgrade!
Now both the GMA 950 and 900 are fully supported. On GMA 950 side, Asus 1005HA support has been added. This release comes with a stable version of GMABooster Power Plan Watcher (component capable of realtime switching of GMA core clock based on a selected Windows Vista/7 Power Plan) and with a set of the Quick Presets for 166/200/250/400 MHz (Quick Presets are available via Windows® Start Menu and can be used for automatic applying of the desired GMA core clock on Windows startup).