I have an RX580 and two monitors; one connected to the HDMI output and the secondary to a DVI-D port through a DVI-D to HDMI adapter. The PC and the main monitor are connected to an UPS and the secondary monitor, that also is a TV, is connected directly to AC mains.
Around here the mains is 220AC and when the voltage drops to 208V the UPS change its internal transformer coil to compensate the output voltage and some times the secondary monitors goes black for about 5 seconds and in some situations, when the secondary monitor tries to reconnects to HDMI, makes the main monitor goes black too for a couple of seconds. It seems like the UPS generates some kind of EMF spike or so.
There's something that I can do to avoid or at least reduce this effect?
Best Answer
As implies in @John post the issue is highly unlikely to he EMF but rather the transfer time of the UPS switching to/from mains.
There is not much you can do about this without changing/adding hardware. The most correct approach would be to change to (an unfortunately much more expensive) type of UPS - the double conversion UPS @gronostag mentioned.
Other (less likely to work/less optimum options/mitigations)