Magento 2 performance tuning

[Keith Smith]

Hi,

I am experiencing performance issues with a Magento 2 install.  The app 
is sluggish however the server does not appear to be under any real 
load.

Magento 2

Hardware server with 2 RAID1 SSD's.  One SSD pair is for Magento and the 
other is for the DB.

The server has 2 CPU's with 4 cores each.  And there is 16G of RAM.

Load is around .56 and will go up to 1 once in a great while, like when 
I list out 500 orders.

Apache is configured as FPM (FastCGI?).

PHP memory_limit = 2048M  (this seems like a lot, however I am reading 
Magento wants a lot of memory)

MySql is set at 12G cache

Any thoughts are much appreciated.

Keith