Some mod performance problems

[kyu1x]

So im running on a 1.6ghz nvdida geforce 8300gs computer w/ 1gig of ram:

 

Here's my problem, I'm running Oblivion on 640x480 with large textures, 35%tree, 25%item, 25%object, 30%spec dist, 30% grass(w/ lowpoly), with int and ext shadow just 1 bar ahead w/ low shadow filtering and i get around an average of 23fps. Now this is with a bunch of performance mods like:

 

De-paralaxer

op. optimization (i only get a boost of 2-3 fps for some strange reason)

streamline(don't use anymore as it caused MORE stuttering)

quiet feet max

oblivion script optimizer

 

From all these mods, I geta pretty small increase of overall just 7-10fps boose, It just annoys me.

I really don;t like losing alot of quality in the game and i know my specs suck, i just thought i'd get something better than this. I just want to know if there are other ways to increase performance.