Ive tweaked oblivion to run well on my system. The sound used to pop wildly, I dont remember how, but I fixed that. It was processor lag.
I personally like morrowind a bit better. Its so much more..well, absorbing. Oblivion just seems like a game. Morrowind seems like a story.
Everything feels the same, the leveling feels useless.
It goes in morrowind from nix hounds killing you to you killing Dremora Lords. In oblivion it only feels like you get that strong after you get a full suit of heavy armor and a strong weapon. You cant just level up and be stronger.