What the heck kind of app have you designed that the _fastest_ response is 2.5 seconds??? Are you crunching data for the human genome project on a legacy Oracle db???? (Okay.. that was a bit facetious..)
On a serious note, you indicated that the CF Server 2016 was using initial (ie default) CFAdmin settings. Perhaps you should have researched what settings need to be modified in order to get optimal performance from CF _before_ testing, so you would get more realistic results. Putting it on a system (physical or VM) with 128G of ram isn't enough; you probably need to adjust Java heap, and other memory / processing settings to match what you are doing with CF Server.
Have you performed any monitoring to determine what the bottleneck is? 2.5 - 5 seconds seems like a lot. I've used CF10 on Windows 2012 Hyper-V w/only 8GB allocated to the OS (w/3g heap) and most CF-related response time is under 300ms.
Have you considered used Fusion Reactor (or enabled internal debugging) to determine what may be slowing it down?
I know that the application is not perfect (I had to take it over from someone else), so second step for sure will be to optimize.
Currently my problem is the transfer from the old to the new hardware platform, where I see a huge difference between a simple i5 PC which is much faster than the server machines.
I guess it has something to do with the hardware configuration and/or Hyper-V and not with CF settings itself.
I would appreciate if anyone has some hints on where to look at.
Does it run a database back end at all?
Moving a database can slow things down until index and statistics have been rebuilt.
You will need to give an idea of what is taking so long. Isolate a small bit of code and see if that takes just as long.
It could be anything in your code or the server, this issue is too broad to say where to look specifically.
Yes, I'm using a MySQL database which is located on a dedicated server. All of the mentioned setups above used the same database.
If I check the debug output, all database queries (response time) are OK.
The problem seems to be in the CFCs, they are take a very long time to complete. Also the CPU of the computer is going to 100%, but only on the server machines, on the i5 I don't see this behavior.
Without knowing what it is doing then its really hard to tell. There is obviously some code in there that is struggling but without know what it is or what its doing the answer could be anything.
You need to isolate sections of it and see if you can find the exact part. Using the CF server monitor or something like fusion reactor to see what part of the code the server is stuck on when it happens is the best place to start.