I need to create a load test for a certain number of requests in a given time. I could successfully setup Precise Throughput Timer and I believe I understand how it works. What I don't understand is how other timers, specifically Gaussian Random Timer would affect it.
I have run my test plan with and without Gaussian Random Timer but I don't see that much of difference in the results. I'm wondering whether adding Gaussian Random Timer would help me to better simulate my users behavior?
I would say that these timers are mutually exclusive
If your goal is to mimic real users behavior as close as possible - go for the Gaussian Random Timer because real users don't hammer the application under test non-stop, they need some time to "think" between operations, i.e. locate the button and move the mouse pointer there, read something, type something, etc. So if your test assumes simulating real users using real browsers - go for Gaussian Random Timer and put realistic think times between operations. If you need your test to produce certain amount of hits per second - just increase the number of threads (virtual users) accordingly. Check out What is the Relationship Between Users and Hits Per Second? for comprehensive explanation if needed.
On the other hand Precise Thorughput Timer is handy when there are no "real users", for example you're testing an API or a database or a message queue and need to send a specific number of requests per second.