Does This Debunk the "Coolant Can Flow Through the Radiator Too Fast" Idea???

I replaced my water pump yesterday and decreased my water pump pulley size and saw a decrease in temp of around 10-12 degrees.

Was it the pump?( flow cooler)

Or was it the pulley?

I figured the pumps efficiency (if truly more efficient) deserved an increase in speed as it was 1:1 before the swap. Crank is 6” water pump pulley is now 5”. Water pump previously was 6”.

Still too hot in my opinion at 195-197*