@smlong : No, at least one executive at EA has stated that the XBox 360's performance is maxed out:
Speaking to OXM UK at E3 2009, senior VP of EA Games Europe Patrick Soderlund told the outlet that "we'll see developers...getting to understand the PS3 better and I think that we're getting more power out of PS3 right now," adding, "I think that we've maxed out the 360 but we haven't maxed out the PS3."
Soderlund's comments refer to the Xbox 360 hardware, which is based off older technology than Sony's PlayStation 3, which has the benefit of a Blu-ray drive and a more powerful CPU in the Cell processor.