hey buddy !
this is just a guess forgive me if I'm wrong, maybe this is about Oblivion.ini (oh my God ... Lex ! you beat me to it XD lol )
- you can try set uGridsToLoad to 5
uGridsToLoad=5 - Increasing the uGridsToLoad value (always in odd steps of 5,7,9,11 etc.) will increase the number of grids around the character in which full texture data will be loaded up and visible as he/she wanders around. This clearly improves visual quality - removing blurry distant LOD textures for example when set to 11 or above - however it also noticeably increases loading times and loading pauses, introduces visual anomalies (particularly around water areas) and reduces performance significantly. Interestingly, as uGridsToLoad increases, the system automatically increases the uExterior Cell Buffer value to accommodate the greater cell data. Furthermore, if you use an even value, the engine will automatically raise it to the nearest odd value (e.g. entering 10 means the engine will set it to 11). On balance the default value of 5 is a good compromise between performance and loading pauses.
- you can try set bUseWaterDepth to 0, but you must be prepared for visual quality loss if you not using OR. if you using OR, somehow this not affect at all, your water will always GREAT. OR really override all water in Oblivion is you turn that feature ON
bUseWaterDepth=1 - If set to 0, water becomes completely opaque (i.e. you cannot see into it at all from above). This can resolve some of the visual glitches which result from changing the uGridsToLoad value, and can also improve FPS, at the cost of some realism.
- I suggest you change this too, if you change bUseWaterDepth for better FPS
uNumDepthGrids=3 - Also appears to control the depth of water visible, with lower values making water less transparent. If set too high this results in glitches, but if set to 1 can resolve issues with the uGridsToLoad value being higher than 5 and improve FPS as well.
reference : http://www.tweakguides.com/Oblivion_7.html