well, the entire point of cache is that you hope that the majority of your data is in your cache which is one die so you don't have to go off die and search for it in memory. That's where prefetching came in for Intel

You said that if the larger cache failed, then they'd use smart cache. but the only thing that smart cache was...was the ability to divide the L2 cache up among the cores.So i don't see how that would take over if your data wasn't in memory.