As aurdino uno have 16MHz oscillator but while running program it have less frequency because some of the processing power is used for running the program. I have used the delay(1) but it giving me around 500Hz.

My questions:

1.is there any way to achieve more than 500Hz?

2.what would be the maximum frequency of digital signal for below program?

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);          
  digitalWrite(13, LOW);         
}