i ran morrowind on my netbook once. i used a bunch of mods for preformance boosts. i cant remember them. there was also a 3rd party program. cant remember any of them for the life of me.
Well it's powered by a dual core 2.1ghz Intel, so with just the plugin-less mods I get 30-60fps indoors (fps is capped at 60), 20-30fps in the wilderness and 15-25fps in towns, so the system performance is already tight. It's just I normally run a whole bunch of mods to add more atmosphere - CoM, MCA, CreaturesX, Realistic Wildlfe, abots wildlife mods, and it's all those additions that kill the FPS.
Worth it though, once I got used to the additions, the world seems so dead without them.