Alienware is "amped" about about Radeon

"The ATI Radeon™ HD 4870 X2 are the highest grade of graphics cards available, and they'll handle pretty much anything you can throw at them. They've each got 2.4 teraFLOPS of graphics horsepower, 1600 stream processors and 2 GB of GDDR5 memory. Their increased video memory delivers incredibly detailed graphics, sharp images and smooth video. If you're really serious about experiencing all that these GPUs have to offer, you might consider getting an Alienware Area-51 ALX with a few of those ATI Radeon HD 4870 X2s inside."