Ruby on Rails performance on EC2 large instance

Hi,

I’ve tried to install and run the benchmark script at https://github.com/TechEmpower/FrameworkBenchmarks but I never got as much performance as it stated on the website at TechEmpower Framework Benchmarks

The peak performance we got is around 450 requests/second. The result from them is 750 requests/second.

Could someone help us? I think we may did some mis-configuration.

Thank you!