running command block checks repeatedly replacing blocks creates "server" lag

After 30-45 minutes causes server lag
possibly due to blocks being replaced with other blocks 3/4 times a second or possibly due to 15/20 zones being checked for blocks or players.
mobs moving slowly
redstone takes 4-10 seconds to update.
block placing and sound of block placing is 10-12 seconds behind.

NOTE: NOT hopper related. NO hoppers on map!

added screenshot

have recently removed some commands to see if it helps but still get issue even with only half of comands running..