SureAI

After you kill those small bony creatures (I forgot their name) the game becomes extremely slow in that map, about 1FPS or so, to the point where it is impossible to fight the other creatures. I have a pretty good system, so it is not because of my computer.
Did anyone else experience that?

No, but I had something similar in the battle of Cahbaet.
The reason was that one of the corpses fell onto some crooked static and started shaking spastically up and down. Unfortunately this is an engine bug and the best one can do is to disable the corpse using the "disable" command in the console.
But check out other reasons first: maybe some program (antivirus, Windows update, messenger, Skype) suddendly started pulling CPU power.

Thanks for the reply.
How exactly do I use the disable command? I am not familiar with Oblivion and the console command (I do know how to enter the console though).

You enter the console, click on the corpse with your mouse, and write "disable".

Thanks, will try that next time I get there.