The board partners want to remain anonymous of course and thus we can’t guarantee that the following details are one hundred percent correct. Based on the information we received during our conversations it seems like the Ati Radeon HD 4890 (Single) will compete against the Geforce GTX 260 and not the GTX 285, since it seems like for the Ati Radeon HD 4890 only the frequencies of the GPU and the memory were increased.

Link