I also have every graphics mod I could get my mitts on
This may be part of your problem.
The other part of your problem is that Oblivion (I'm assuming this is what you're playing and not, say, Daggerfall) is very much CPU bound because it only makes good use of one of your cores. You could have pretty much any graphics card from the Nvidia's 8800 on up and it'll run about the same.
Use http://www.tesnexus.com/downloads/file.php?id=23208 if you aren't already, that will clear up a lot of stutter (most of which has little to do with actual hardware). If you don't have a dedicated sound card you should 1. Get http://www.tesnexus.com/downloads/file.php?id=15942 and 2. Get a dedicated sound card already you caveman. Get a low poly grass mod too, grass is a terrible resource hog. I use http://www.tesnexus.com/downloads/file.php?id=33403 at setting 2 and "Short" length. Looks better than the original and runs a lot faster too.
You could also always try overclocking your processor more :flame:
And next time just post in the Oblivion Hardware section, this is for Skyrim discussion.