That sounds low. Have you done the multithreading tweaks in Oblivion? I get 30fps in 1280x1024 with detail sliders around 3/4 of the way up, and I have an old P4/3.20GHz (32bit/HT) with an AGP8X 7800GS graphics card. If you want the tweaks I used to achieve this, let me know since they should boost performance of the game whether you're in Wine or Windows.
