That display is not documented as to what each dot indicates by Microsoft so a reason can not be told until Microsoft releases such information. However if you dive into the machine you may find that on boot devices such as wifi and other may take a second to initialize and cause the pause on said display.
I don't expect the cause to be found here. Not for a lack of trying, but for the lack of documentation and boot diagnostics.
Just want to ask one question,on my notebook when windows XP starts and it shows XP logo with a horizontal animated three-dash scrolling bar, this scrolling bar stucks during scrolling for just few seconds( 2 to 3 times or so). According to the vendor it is normal and I found it so on other brand new notebooks in the show room. Is it so?
I don,t know it,s true or not but just my observation that this phenomenon is seen in most noteboks even the best ones but its very rare in desktop even the cheepest ones!