Significant Arduino execution delay every time I open Serial Monitor

hello,
recently, i've run trouble involving serial communication arduino.  every time open serial monitor, execution of code on arduino seems pause significant time (10 seconds or more).  when execution resumes, millis counter has been reset, else proceeds normal, when close monitor.  only when open monitor problem occur.  i have not had problem, , until arduino worked normal.  i have tried reinstalling drivers, using different computers , cables, changing com port in device manager, , removing , re-downloading arduino software on computer, no avail.

specs:
windows 7 ultimate
arduino mega 2560 on com3
usb connection computer
nothing besides usb cable attached arduino

the problem happens regardless of whether i'm running sketch uses serial communication.  for example, when  i run example blink code, @ first works fine, , led begins blink.  as open serial monitor, led freezes in current state.  after 10 seconds of serial monitor being open, led once again begins blink usual.

when run simple serial code, same results.  the tx led begins blinking after deploy code.  as open serial monitor, however, led stops blinking.  after delay, begins display times, starting 0.  every time close , re-open monitor, millis counter resets 0.

code: [select]

void setup() {
 serial.begin(9600);
}

void loop() {
 serial.print("millis: ");
 serial.println(millis());
 delay(1000);
}

any ideas causing this?  at first, suspected software issue, i'm worried arduino may damaged somehow.  any help, ideas causing problem, or suggestions appreciated.

edit: never mind, bad.  apparently arduino boards auto-reset when serial monitor opened, resulting in delay.  i'm not sure how didn't notice delay earlier.  sorry unnecessary post.

quote

...the execution of code on arduino seems pause significant time (10 seconds or more).

a different bootloader reduce time.  believe optiboot takes 1 second start sketch.

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