I have very strange issue with Windows server 2008 R2 with IIS 7.5 installed on server with cpu with 24 cores and 24 GB ram.

The problem is that with apache benchmark tool I can't force the IIS to serve more than 17-18 request per seconds. I am addressing very simple asp page that just print a text without any connections to database or whatever.

With 1000 users and 1000 requests the response times are around 120-150s.

Very weird. Any idea what could be the reason for such low value of requests per seconds served?

I tried very different settings and nothing helped.

UPDATE: the low performance is when requests come from a host which is not in the server network. If the benchmark is started from a host in same network the throughput is about 1000+ requests/second

migrated from stackoverflow.com Aug 12 '12 at 10:05

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  • This is more a question for Server Fault. Is the CPU maxing out? If yes, which process? Did you analyze the problem with performance counters? – Marco Miltenburg Aug 2 '12 at 11:03
  • Hi Marco, thanks for the comment. The CPU is with very poor utilization. Even with concurrency 1000 and 1000 request the CPU stays lower than 20%. In the same time the response time is very high. – Nikola Yankov Aug 2 '12 at 11:48
  • What is the bandwidth and ping time between the test machine and the server if they are not on the same network? – Marco Miltenburg Aug 2 '12 at 19:34
  • The bandwidth is 30Mbps, the ping time 50-60 ms. – Nikola Yankov Aug 3 '12 at 6:48
  • Can you post a screenshot of the performance counters for the (classic) Active Server Pages counters, or in case of an ASP.NET app, the performance counters of the ASP.NET application pool while the server is under load? – Marco Miltenburg Aug 3 '12 at 10:56

This may be a DNS timeout. Have you enabled reverse lookups in your IIS settings? See if the problem goes away if you add the remote client to your hosts file, or just disable reverse lookups.


If you have normal performance on the local network but not off of the local network you should be investigating the edge network and routing infrastructure. This doesn't sound like a server issue as much as it is a networking and/or firewall issue.

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