[fnl]

Sorry for the 400-100=300MB mix-up, you are completely right, it should have been 800-200=600MB.

If you need to crunch all those numbers at once, then yes, your cache will become your bottleneck. But if you were, say, keeping the count on a 100 million things, you most of the time will not be worried about that or your RAM usage, as most counts typically tend to follow a power-law distribution. Therefore, contention to make sure you are tracking every count will probably become a far worse problem for your app than your ability to shuffle data to/from the CPUs. Only in the corner case where you crunch a matrix or vectors or numbers of that size at once, you will start to get worried. But as said, I think the tensor-crunching use-case is the exception, not the norm.