DVI on the computer side can be either analog or digital signaling. Make sure you are using only DVI->DVI cable and not DVI->VGA cable.
HDMI is digital only.
DVI and HDMI normally use a digital format so if the connection has problems, the entire link just drops out. I've seen 'fuzzy' issues caused by the format converter in the monitors. As an example if your computer is set to any other resolution then the native mode of the monitor, the format converter will add 'fuzz'. You might try different computer resolution settings and see if any of them have a none 'fuzzy' look. The best one is usually the native mode for the monitor.
Also depending on the cable and if you are using DVI to VGA adapter, then the connection is in the analog domain and 'fuzz' is much more likely while using analog. Check to make sure you're using only DVI to DVI connections. The HDMI connector on the computer is digital only so HDMI to DVI adapters will work fine.