CPU : Celeron 450MHz
Mem : 256MB
OS : Vine Linux
HTTPd : httpd-2.0.50

Server Software: Apache
Server Hostname: localhost
Server Port: 80

Document Path: /index.html.en
Document Length: 1456 bytes

Concurrency Level: 10
Time taken for tests: 21.914001 seconds
Complete requests: 10000
Failed requests: 0
Write errors: 0
Total transferred: 17350152 bytes
HTML transferred: 14560000 bytes
Requests per second: 456.33 [#/sec] (mean)
Time per request: 21.914 [ms] (mean)
Time per request: 2.191 [ms] (mean, across all concurrent requests)
Transfer rate: 773.16 [Kbytes/sec] received

これってPCの性能から考えると妥当なんですかね・・・・？
とくにチューニングなどはしてないのですが、一秒間に456回以上アクセスがあると、
処理できなくなるという結果か？？