I haven't seen any lower-res numbers, but by reading the quadfire review on the [H] front page it didn't look good for higher res. There just isn't enough RAM on any 512MB cards to handle it. However, that article did state that at 1280x1024 with 8xAA enabled the game was playable so there is hope for lower resolutions that won't use as much video memory.
The benefits of running at a higher res seem to outweigh the benefits of AA if your monitor can handle it. Haven't seen any other reviews out there yet with the 8.3s and UT3.