Let me preface this by saying I'm as skeptical as anyone about equating neural structures with traditional computing hardware (e.g. 'how many MBs is long term memory?'), but episodic memories seems like one place where talking about storage capability seems warranted, since episodes are quite discrete.
I've heard discussion about the hippocampus being able to store all of the relevant events for the past 10 years, and that it slowly transfers its knowledge to the cortex, which has a much higher capacity. But how many separately encoded events can it hold? I know it uses a sparse coding scheme to keep related memories separate, so it should be possible to infer capacity from the size of the neural populations involved and the average activity. Has someone looked into this before?