Hello !
My problem here is that the dead NPC are disappearing in terms of minutes ( while it takes a lot of time in the Vanilla )
It caused by the optional perfomance pack , but it happens even without it.
So my question is:

Are there any console commands/ini tweaks/mods that help me with that ?

http://skyrim.nexusmods.com/downloads/file.php?id=3084 has an optional esp which allows you to tweak how long until dead bodies start being removed it also lets you choose how many you allow on screen as well...might come in handy.

Can't understand how to use it , help ?

EDIT: Sorry I see now..