I suspect the bandwidth and memory controller issues won't be as bad as they are with the 2990X, which produces very schizoid performance depending on workload due to its strange configuration. At least all dies will have direct memory access through the I/O die, and won't have to make the extra hop. However, we are seeing, in effect, a doubling of cores without a corresponding doubling of bandwidth. No doubt AMD has better, faster memory support, and has addressed some latency issues with their memory controller too (though moving to the I/O die might cancel out some of those improvements). However, they will not have anywhere near double the bandwidth. So I don't doubt that there will be certain instances where core scaling will run into a bandwidth wall. Still, that doesn't matter overmuch. So you won't see 100% core scaling. So what? It won't be schizoid like the 2990X, at least. And you're still getting more cores for the money. It's a good move by AMD.