I assume you are talking about getting a laptop for these cards are mobile video cards. If this is case then I recommend getting a laptop that has a dedicated video of at least 128MB or 256MB. Dedicated anything is the way to go and I learned something last month.

My friend has an Alienware laptop and it has 256MB dedicated video on it. It's a 15.4" WXGA laptop but having a dedicated video card will enable it to have 1680 x 1050 resolution which is really good if you don't mind sizes that small.

So as long as its 64MB or higher dedicated, the X600 is what you will want for a laptop that will play some good 3D games.