To some extent true, but when core counts increase, they tend to double. Given the very new version of PG and Linux required to get these scalability benefits, it is nice to seem them pipelined ahead of the EC2 curve...it takes a long time and a lot of work to correctly alleviate lock contention and get new versions of Linux disseminated (the new LTS from Canonical will do a lot...I believe it features 3.2)