Why node.js+mongodb does not gives 100 req/sec throughput for 100 req sent in a second?

Question

I kept node.js sever on one machine and mongodb sever on another machine. requests were mixture of 70% read and 30% write. It is observed that at 100 request in a second throughput is 60req/sec and at 200 requests second throughput is 130 req/sec. cpu and memory usage is same in both the cases. If application can server 130 req/sec then why it has not server 100req/sec in first case since cpu and memory utilization is same. machines are using ubuntu server 14.04

Answer 1

Make user threads in Jmeter and use loop forever for 300 sec. Then get the values.