I have a very high load scenario. 650+ clients and 1M DNS queries per hour (Yes, that's correct). Pi-Hole is running a custom blacklist with around 3000 domain names. There is no Ad blocking or any other list, only our own custom blacklist.
Hardware is a 16GB RAM, i3 - 3220 CPU 4 Core
We see CPU utilization creep up and hit a full 100% over a 24 hour period. It starts okay at around 5 to 10% CPU and then the CPU utilization increases to almost 90-100% over 24 hours. Restarting the pihole-FTL resets everything and the cycle begins again.
Should I look at upgrading the CPU and get a more modern faster CPU. \
Any recommendations to what CPU would be good enough.