You meant a 128GB (instead of 12GB)? And yes, a L4 cache can be one way out of that problem. Another way is making the L3 cache lines wider and working the hel

You meant a 128GB (instead of 12GB)? And yes, a L4 cache can be one way out of that problem. Another way is making the L3 cache lines wider and working the hell out of improving your management algorithm. It's not a theoretically impossible problem. It's also not something you can solve automatically with a bit more money or some simple decisions. It's possible this is the best architecture available, but it's not certain by any means.