Bit late on the uptake, but there is this ol' doohickey called the 64Hz bug. Y'see, what Bethesda decided to do in the subsequent revisions to their renderer post Morrowind, was implement the usage of GetTickCount().
Ever wondered why some games look smooth @ 30 fps, and others choppy? The choppy games, chances are, are using GetTickCount() in their renderer.
There are two ways to fix this for Oblivion/Fallout 3/Fallout New Vegas. #1 Is to cap your framerate to the minimum you experienced during play, and set iFPSClamp=##, with ## being your minimum framerate. This also works with Skyrim. Fallout 3 and New Vegas have bugs with the player model when using this ini edit.
Option #2 is to use Stutter Remover and enable the setting that is along the lines of bReplaceGetTickCount(). This is the best option. This will only work for Oblivion/Fallout 3/Fallout New Vegas, as only those three games have an SR mod for 'em.