Timing Gear Question

[BTERRY29]

I have read somewhere that a cam gear with excessive backlash will "let you know it". I assume that means it will make noise. My question is, would this noise be present at all times, or would it be more prominent at idle vs. under load. My initial thought is that at idle, there is opportunity for a clatter, but under load I would think the gears would be under more direct contact with the chances for noise might not be present? Or would it be the opposite, were the gear is quiet until loaded up? Anyone have any direct experience with excessive lash in a running engine? For the sake of discussion, lets assume an aluminum gear.