Xbox 360 is unified, you never have to loose cycles to adress the other 256MB ram, like you have to do on PS3
Also the GPU uses unified shaders which practically are utilized 90%+ comparing to 60%+ of the separate ones, again anything PS3 has more in raw power, 360 surpasses easilly with design
The shader pipeline is also wider and with above SM3.0 specs than a normal DX9 card PS3 has
And the 10MB EDRAM help both free ram and bandwidth in a huge way
It doesn't... 'All' it does is make some pixel shader operations 'free'. You all do know that XENOS is actually divided into 2 parts, one is main die and another is daughter die, don't you? Main die can give jobs and data for daughter die to process. Daughter die is dedicated for pixel shader jobs and 'gives' for example AA for 'free' if used correctly.
It looks like this,
You can see daugter die with naked eye.
So its actually 2 'cores'(Or more like dies or units) not one. :P
And for X360 maxing its limits... Uhm, saying X360 is maxing its limits is like saying all that PS3 can do is what unreal engine can do. I think PS3 will max its potential much faster than X360. It might be that X360 potential is never maxed(As all devs seem to use unreal engine or already done/not optimal engines for X360.). Well, I don't blame devs because its much cheaper to buy engine than make one by themselves. It also cuts nicely development time. (You know... Less waiting... :D)