Oblivion still stutters?!

When i run around outside in oblivion, i get a horrible load stutter. (this doesnt happen inside cities, houses, or dungeons) For example, im traveling on the road with my horse, and the game runs smooth until objects, usually trees, rocks, or ruins, have to load in the distance. Then i get a stutter for 5 seconds and everything is back to normal, until it has to load something again. I think its related to the pop ins that occur after the stutter. Can someone help me resolve this issue?

Things ive tried:
memory tweaks on tweakguides.com
uninstalling and reinstalling
playing vanilla oblivion
running on very low
ifpsclamp=60 and 75 (game runs in slow mo)
Operation Optimization
Streamline
Reinstalling and removing codecs
clean boot
Defragging
updating video and sound drivers

specs:
EVGA 790i ultra sli
e8400 @ 3.6 ghz
4GB DDR3
GALAXY GTX 260+ 896MB
250GB HDD x2(raid 0)
1000 watt PSU