There are a slew of sites hosting various details on AMD's 4800-series (aka RV770) and its supposed arrival next month, but TGDaily's got the best overall write-up, imo. Hit the link for the full, two-page read.

"The new GPU has 480 stream processors or shader units (96+384), 32 Texture units (up from 16), 16 ROP (same as 2900/3800), a 256-bit memory controller and native GDDR3/4/5 support (expect GDDR3 and GDDR5 memory versions of RV770 cards)."