A620M Pro RS - 5 Beeps but everything is working

It sounds like the board isn't properly detecting the display. It isn't an issue
if the system is functioning correctly otherwise. If it's bothering you then you
can try different display cables/outputs until you find a combination that eliminates
the beep code. Alternatively you can disconnect the PC speaker (if you have one
connected).

This kind of thing happens because of how complicated Display output standards
have become, same pin outs etc but different firmware specs. It's only ever an
issue if you are not getting a display at all, in which case it's most often
the cable that isn't compatible with the signal and/or display.

I hope this helps, enjoy the system