Not sure if anyone else has run into this, so here goes...
System Specs:
AMD Athlon 64 X2 4600+ 2.4GHz
2GB DDR3 RAM
SATA HDDs
ATI (Sapphire) Radeon X5850 1GB GDDR5
Problem:
Able to run vanilla Oblivion with max settings and get decent framerates. Around 60-70 FPS indoors and 15-20 FPS outdoors in heavily wooded/grassy areas & Oblivion gates. Travel to Seyda Neen using Morroblivion Chargen And Transport Mod v6. It looks great...but only getting around 5 FPS even without the Visual Overhaul installed.
Workaround (kinda):
Using Streamline 3.1 http://www.tesnexus.com/downloads/file.php?id=10400 does get much better framerates (from around 10 FPS up to 60 FPS outdoors). Of course there is a visual trade off for the framerates.
Question:
Why would there be such a FPS hit from vanilla Oblivion to Morroblivion (Morrowind) ?

Possibly
Possibly because the meshes aren't as optimised? SINCE they were originally created from the converter. I have a MUCH lower PC power
2 Gigz ram
128mb graphics card
2.16 single processor
Vista Home Premium
An oldie, recently repaired, but I get a 'fast enough speed to have fun' FPS. In Morroblivion its actually not that bad for me. I have yet to use visual overhaul but I've applied the weapons retexture. Does anyone know if I should use visual overhaul with the specs above? Really tempted... Do these meshes/textures make the game more stable?
Hmmm Perhaps an optimization mod should be done, I would do it but... last time, kinda made oblivion ctd.... a big mess you see.