I currently use Intel GMA 945. Recently I heard that there are a software that can increase the performance of Intel GMA, named GMABooster.
I give it a try, clocked it at maximum 400MHz. When I play EURO 2008, I notice the graphic become smoother than before. It really works.
GMABooster is freeware, but the license die weekly, so you have to download updated free copy which also lasts a week. If you kind enough to donate, you will receive serial which registered the copy of your GMABooster forever.