Originally Posted by
spursindonesia
One thing seems true in this new gen GPU from AMD, the buswidth isn't affected by the number of ROPs as previously done, since it has been decoupled in the new GCN mArch. A Tahiti Pro aka HD 7950 can retain 384 bit buswidth and 3 GB configuration (though perhaps with lower clocked memory chips) even with lesser ROPs and SPs compared to its bigger brother.
EDIT:
Well, going by the latest rumor like the one in the first page, it seems HD 7970 will be ~ GTX 680, since NVidia's new gen chip won't be the big daddy one, though not quite that small either. The big daddy, might arrive later this year or early next year, when TSMC's 28 nm process getting more mature and less risky. We might see parity from both camps after long, long time.