1. Has it always been like this? If not, has something changed recently with your set up? 2. Is it only on specific games? If so, which games? 3. What Graphics Card do you have? What driver version are you using?
The white dots can be caused by using HDMI extension cables or HDMI A/B switch box. If you are using either one, try it without and see if that fixes the problem, if it ends up being a extension cable, the quality and / or length of the extension cable may be the problem. If using a A/B switch box, then chances are the switch box is for a older HDMI standard. Regards: Jack