Great tutorial in the post just above.
But you might as well add the special profiling Steam branch for Arma 3 following this wiki page : https://community.bistudio.com/wiki/Arma_3_Steam_Branches.
In short :
- Right click on Arma 3 in your Steam Library, then Properties
- Select the tab BETAS
- Enter the code CautionSpecialProfilingAndTestingBranchArma3 then click CHECK CODE
- Finally, still in this BETAS tab, use the dropdown list to select the branch profiling - Performance Profiling Build
- Enjoy ! This will ALWAYS be up to date, guaranteed without pain (because finding the dropbox link, downloading, extracting and renaming everytime can be boring after a few times)
PS : And don't worry, although the branch is named Profiling, by default it will launch the correct arma3.exe that is the performance version, and not the profiling one (not 100% sure though, if Dwarden could confirm :P )