UPDATE

[addendum] Note : if you use the "tdt" console command below after installing the current 1.1 patch for Oblivion you'll find that instead of just the few lines of FPS related debugging text that it'll now list a huge chunk of text to do with texture and assets paths as the game parses them into memory. This blocks from view pretty much the whole left hand side of the screen when in the small resolutions. AS it's part of the 'debugging' facility of the game itself it doesn't appear that they can be disabled from showing.

[9th Apr 06] Morrowind's command of "show FPS=0/1" doesn't work in Oblivion so to display Oblivion's FPS using the engine rather than an external appilication like Fraps or ATI Tray Tools, type the following command into the console (hit the 'tilda' key, '~', to access the console; if you're in the UK it's actually the '¬' key which sits to the left of the number '1' and not *our* '~' key. This toggles, show/hides, Oblivion's in game console for the PC version of the game);

• tdt

After typing this command you should then see a 5 line block of text in the upper right corner of your screen; FPS is listed on the 1st line.

[30th Mar 06] Be careful using the bDoSpecularPass=0 performance tweak, it can cause Oblivion to fast crash back to the desktop when in certain areas; Skingrad Castle courtyard for one.

Disabling dDoSpecularPass also appear to be responsible (in whole or in part) for terrain not being effected by fog weather effects; this is where objects in the world - trees, plants, buildings etc. - appear correctly fogged, but the ground surface doesn't, giving the other objects a sort of 'milky' appearance.

For now, it's probably best to leave dDoSpecularPass at it's default setting of '1' (specular highlights enabled).

Terrain fogged correctly when bDoSpecularPass is set to '1' (default "bDoSpecularPass=1")

Terrain incorrectly fogged when bDoSpecularPass is set to '0' and turned off ("bDoSpecularPass=0")