I'd assumed it referred to aggregate bandwidth, and indeed that seems to be the case after testing. Throughput to a single key still remains around 600mbit/sec

I'd assumed it referred to aggregate bandwidth, and indeed that seems to be the case after testing. Throughput to a single key still remains around 600mbit/sec within a region, and meanwhile the real problem with S3 isn't throughput so much as latency, and no amount of bandwidth will help that.