I tried performance testing with and without wincache on php7.1/IIS7.5/M3.3 . Wincache was confirmed working using the status page that comes with the dll download, wincache2.php to monitor statistics.
I used jmeter to simulate visiting a couple courses with many activities and resources and clicking on a couple course resource links. Each page request used 'Retrieve All Embedded Resources' under the Advanced tab for HTTP request.
I did not see any significant difference in jmeter 'Throughput' and 'Received/KB sec'
I also tried the Moodle 'Caching->Test Performance' for 10k users and did not see any significant difference under the Application Cache->File cache section.
Seeing as iis.net and php.net recommend using wincache Im guessing my implementation or testing is done incorrectly. Any advice on how best to test performance? Or wincache configuration settings (I only enabled it)?