I'm a PC user, but have you tried installing the entire game onto your HDD to speed up load times? It may also help with freezing, assuming the freezing is caused by disk-read errors.
Load times are always fairly long with Gamebryo games (e.g. Oblivion, Fallout 3). Even fully installed on my 6-disk RAID-0 partition it takes 5-10 seconds or so on each transition (may not sound like much, but my PC is FAST, and it's a long time compared to other games I have).