Your biggest constraint is programmer productivity, not server performance. Your concerns are further diminished ~ every two years. Please re-evaluate your as

Your biggest constraint is programmer productivity, not server performance. Your concerns are further diminished ~ every two years. Please re-evaluate your assumptions on that timeline. This position was established by the company that owns the one of the largest server farms in the world? Are they looking to save on a few x-large instances? Seems short-sighted to me. Sub 50ms response times are very achievable with Rails. Throwing another server at it is a very reasonable response. Especially when you want your team to remain productive in a cohesive, batteries included framework. Plenty of real-world Rails examples to demonstrate this.