You can have a look at this website which has a bunch of benchmarks... Notebookcheck: Mobile Graphics Cards - Benchmark List
There is also a comparison listing the tiers and what each graphic card can handle at this link... Notebookcheck: Comparison of Graphic Cards
Lastly, there is a chart with how well each mobile graphic card performs in certain games... Notebookcheck: Computer Games on Laptop Graphic Cards
You can decide whether NVIDIA or ATI is better. I think generally Intel + NVIDIA laptops have better processors but worse graphic cards and AMD + ATI laptops are the opposite. I don't think there will ever be an Intel + ATI laptop.