Hi,

I think it is client problem (bandwidth or cpu). This is my short test on your server:

Xeon CPU and 10 Mbit/s line

ab -n 10000 -c 40 http://50.56.117.62/index.html

This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 50.56.117.62 (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests


Server Software: nginx/1.0.5
Server Hostname: 50.56.117.62
Server Port: 80

Document Path: /index.html
Document Length: 423 bytes

Concurrency Level: 40
Time taken for tests: 8.322 seconds
Complete requests: 10000
Failed requests: 0
Write errors: 0
Total transferred: 8440000 bytes
HTML transferred: 4230000 bytes
Requests per second: 1201.57 [#/sec] (mean)
Time per request: 33.290 [ms] (mean)
Time per request: 0.832 [ms] (mean, across all concurrent requests)
Transfer rate: 990.36 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 4
Processing: 5 33 5.3 30 79
Waiting: 5 33 5.1 30 79
Total: 6 33 5.3 30 80

Percentage of the requests served within a certain time (ms)
50% 30
66% 36
75% 38
80% 38
90% 40
95% 41
98% 41
99% 42
100% 80 (longest request)