Optimalisation issues

Hi
I’m trying to install piwik to track website which have ~5M views per day.
I’v installed piwik on VM with 8vCPU and 16GB RAM, disks are able to get ~2500 IOPS
Problem is that whatever I configure PHP7 and mysql, PIWIK is running only one CPU to 100%, other are abatu 5% load, and chart with daily views is generating for about 16 minutes

Am I doing something wrong? Do i need stronger server for this?