- Immediately consistency: 1 box: 2000 requests/second with 5 second response time
- Eventually consistent: 1 box: 300 requests/second with a 100 millisecond response time.
It is all achivable, if you are not there you need tools to figure out why.
Switch to stateless services whenever possible. A great article about pushing the boundaries and how important it is in HFT is available in barbarians at the gateways.