I understand that Algorand is able to handle a lot of transaction in less that 4s. That is why I didn’t understand what is happening in my private network.
Just to be clear, I didn’t say that it takes 0.5s for the first transaction. I am not in dev mode, so my network waits for the next round to create a new block and each round takes around 4 seconds. It takes 40 seconds when I send 90 transactions to the network and wait to get the last confirmation. But the next time I run the experiment and send another 90 transactions, it takes around 40.5 seconds to receive the last confirmation. And if I run the same experiment 10 times more, it would take around 45s.
After I set the flag, I do ./sanbox down dev and then clean. Then I start the network again.