Hard Drive access is definitely a bottleneck for Oblivion and the cause of a lot of Crash To Desktop..
Oblivion will run smoother if you follow these tips with regards to Hard Drives.
– Install it on the fastest hard drive you have (if you have more than one)
Use softs like HD Tack to measure speed of your drives : www.simplisoftware.com/Public/index…?request=HdTach
– Defragment your Oblivion Hard Drive often (softs like Diskeeper have a feature to automatically defragment files based on usage)
– Make sure you have plenty of room left on your drive. This is particularly important if the game is installed on the system drive.
– Disable any background task that would compete with Oblivion for HD access (spyware scans, search engine indexer, etc)
– Disable background music (it worked like a charm for me)
– Use mods like Streamline to better distribute the load of new resources into the game