In my experience, many of the crashes that occurred in a Oblivion were due to memory issues.
After seeing how good of a job http://www.nexusmods.com/skyrim/mods/50305/? mod does to alleviate crashes in Skyrim, I was wondering if it will ever get implemented into Oblivion via a mod or OBSE update (unless it already has and I'm unaware of it, or if it's not possible to make).