Question about the ATI 4570 mobility

Just wondering, is the ATI Mobility Radeon HD 4570 128-bit or 64-bit. I am thinking of getting a Dell Studio 15, and just wanted to know. Dell says 128-bit (http://www1.ap.dell.com/content/learnmore/learnmore.aspx?c=au&l=en&s=dhs&~id=hmc_graphics_inspnnb&~lt=popup&~series=inspn&~tab=details)
but notebookcheck says 64-bit (http://www.notebookcheck.net/Comparison-of-Graphic-Cards.130.0.html).
can anyone help me out?
thx

I am not sure, being dell they could be wrong but they also do get there own stuff made for them, I can not see this being incorrect with Dell. All I can say is if you have the laptop already, print screen it and talk to them, but if you haven't get in touch with ATI and ask them. I have done both as I have this card yet to test games.

I am sorry i can not help more! But i do remember notebook website have 64/128 on it's memory bus going a couple of weeks back.