The response times are normal within 2-3 second range when running in fiddler (while the performance test is ongoing) but the jmeter 5.2 results are >100 seconds for most of the transactions. I have 8 thread groups performing different scenarios and 5 threads for each group. Can anyone please suggest what could be wrong? Im using constant throughput timer to pace the execution for each thread so that the desired volumes are achieved (5/min). Will that be an issue? If so, what is the best option. Thanks you for any help. I need to get the tests done ASAP. Any help would be much appreciated.

1 Answer 1


I can think of 2 reasons:

  1. Given 8 Thread Groups with 5 virtual users you're accessing your application with 40 concurrent users and it might be the case the application gets overloaded hence response time increases as concurrency increases. Try running your test with 1 virtual user. If you get response times comparable to what you see in Fiddler than your system cannot properly handle even 40 users. Check its logs, configuraiton, baseline OS health metrics (CPU, RAM, Network, Disk, Swap, etc.), this can be done using JMeter PerfMon Plugin
  2. If you're using Fiddler as a sniffer for the browser it might be the case that the browser is caching |heavy" content (images, scripts, styles, sounds, fonts, etc). Tick "Disable Cache" in your browser developer tools, it will trigger "clean" sessions (like JMeter does)

    enter image description here

    Going forward add HTTP Cache Manager to your test plan so JMeter would have its own browser cache implementation.

  • The OS i'm running on is a Intel i7 2 core processor with 16 GB RAM. The response times are same even with 8 thread (1 each thread group). Interestingly, when running the test from Jmeter GUI (Which is not recommended but wanted to see what would happen), I don't see any problems until the users ramp up to 16 users. It is only when approximately at 18th user ramps up the response times increase. When running the same test in non gui mode, I see high responses even with 8 users. This is crazy. Also the app is hosted in cloud and there is no access provided to logs/stats/tools by the vendor.
    – Partha
    Dec 20, 2019 at 1:00
  • If there was a pressure on the JVM, I should have atleast seen 1 out of memory exception which didn't happen. All through the test, the CPU is 2-4% and RAM never went beyond 60%.
    – Partha
    Dec 20, 2019 at 1:09
  • The application response times are normal <3 seconds while the full load test is in progress. The results extracted by Jmeter are 40-83 seconds for most of the transactions than the manual response times (3 seconds) recorded during the test.
    – Partha
    Jan 6, 2020 at 0:56

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