I have a nvidia 9500 gt 1 gb of ram intel p4 2.8 ghz .. i try to run oblivion on high settings with bloom and 2x or 4x anti aliasing and the game runs like garbage the fps jumps way to much from like 40 to 15 back to 25 in like 3 secs .. ive seen alot of you tube vids of people running obliviion on max settings with 9500 gt any help to improve my fps thanks..
rubbish, a 9500gt can not run oblivion on high settings, especially not with AA on. What is your resoluton, try lowering that also. A big killer in oblivion for lower end video cards is grass, turn it down or off completely. Also, a pretty decent CPU also helps quite a bit with this game.
The problem with your PC is also the fact that it s P4 2.8Gz. That is basically a huge bottleneck.
Below are benchmarks of the Radeon X1900XT with various different CPUs. Your single core P4 would rank at the bottom between the Intel Pentium D 805 and the Intel Celeron D 351 (both of those are dual core CPUs).
The most important thing to realize is that your CPU can severely bottlenecks the video card. The more powerful a card you install the more restricted it will be. Spending money on a newer card will give you marginal improvements.
The best thing to do is to save up money for a new PC.