Hardware Infos heard samples of the 40nm RV790 have reached ATI's partners. There isn't a lot of information available about the RV790, but it's said to be a 40nm shrink of the RV770 (Radeon HD 4800) GPU.
The German site claims the first RV790 samples are clocked at 750MHz and feature 1GB of GDDR5 memory clocked at 3900MHz - slightly higher than the 3600MHz of the RV770.
The card uses the Qimonda IDGV1G-05A1F1C-40X chips, which are theoretically specced for 4000MHz. By the way, German memory maker Qimonda filed for insolvency last week. Hopefully this won't impact GDDR5 memory supply.