So my intent was really to benchmark how our current app generates reports on php5, php7, and php7-fpm.
I did this by launching a 2gb instance on DigitalOcean with Ubuntu 16.04 and installing apache2 and php7. The test ran in about 9 seconds and generated a report 10 times (ab -k -c 2 -n 10).
Then I installed ppa:ondrej/php and upgraded and ran it again (still on php7.0, but now from the ppa). Result of 16 seconds was a bit surprising. I switched to php5.6 and it ran in 18 seconds.
Then I purged the ppa and restored php7 from the ubuntu repo and it ran in about 10 seconds again.
So why so slow?