Hi .. even though you can find some details in regards to NEW connections per second however, the performance of the sensor is measured based on Megabits per second that it is able to inspect.
For example a basic 4250 can handle 500 Mbps for inspection. its performance is based on 5000 NEW tcp connections per second, 5000 Http connections per second, overage packet size of 445 bytes, version 4.1 or higher.
I hope it helps .. please rate it if it does !!!