Firstly, you must turn off all your other speed up software & caches plugins as these will conflict & give you false results.
To test your site we don't currently recommend using Google Page Speed Insights or GT Metrix as the results of our tests were consistently unreliable - it appears for now at least there is a fault there.
The most reliable results we are getting from Pingdom by selecting the server closest to your audience ... sadly as the other 2 services are experiencing issues so Pingdom is getting the bulk of the traffic & at busy times you'll be stuck in a queue.
We recommend you avoid testing at busy traffic times in your country and you select the testing server closest to your server. Always skip the first test and then take an average of 3 tests - that's a more clinical way of doing it & allows for the cache to build.
If you are testing speed under Cloudflare you WILL get variable results as your site is delivered by Cloudflare nodes & not your server - so you must turn "developer mode ON" to get a real result whilst testing.
Remember that once Cloudflare is enabled your server doesn't deliver your site anymore as it's delivered by the closest node on the Cloudflare network and the cache is handled by Cloudflare (vipercache just acts a code cruncher to make your code thinner)
99% of the time when customers say "it's not made much difference" it's usually as a result of not understanding the process, not bulk optimising graphics, and not removing any laggy themes or plugins...
We have tested the products extensively on 100's of sites & we have speed up code that not even the fastest products on the market use.