According to a post over at Donanimhaber.com, AMD's upcoming Radeon HD 6700 Series graphics cards might use a 256-bit memory interface.

The 256-bit memory interface comes as a surprise considering that the current Radeon HD 5700 Series features a 128-bit memory interface, but it could make sense as all reports indicate that the upcoming HD 6000 series graphics cards are all about evolution.

This also could be the way to keep the available Radeon HD 5700 Series alive as AMD can drop its price and keep selling it until they clear out the stock as thanks to the "evolution" and the wider memory interface, Radeon HD 6700 Series should end up significantly faster.

Judging by some early benchmarks, Radeon HD 6000 cards will offer a significant performance boost over the current generation, but bear in mind that they still stick to the same 40nm production process. Using a wider memory bus could be one of the ways of boosting performance while using the same production process, but it would also increase production costs.

You can find more here.