yes, that's the key. The local IO on previous reported systems was HDDs, thus 300-600Mb/s at best with 6 drives per machine, while this guys are getting 3.3Gb/s. Getting full performance - 1.1Gb/s - of 10Gb network - were they lucky or AWS now is that good ? (couple years ago i was able to get only 400Mb/s node-to-node on cluster compute nodes there)