[SOLVED] LG Ultrawide monitor goes into sleep mode when launching games

[Moralagos]

I've recently purchased an LG ultrawide monitor, model 25UM58. With most of the games I have and were running fine before, whenever I launch them now, the monitor instantly goes to sleep. With some of them, the PC restarts after a few seconds, with others it doesn't. Alt-Tab doesn't work, nothing works except powering off/hard reset. If I plug my old monitor, everything works fine. Changing Windows resolution doesn't solve the issue. LG support says there's nothing wrong with the monitor. I haven't changed anything about the games... the resolution in these games is the same as it was before... please help!
I'm using a HDMI cable, my graphics card is a Radeon RX 480 and my OS is Windows 10.

 

[SgtScream]

Please list all of your hardware component specifications including the power supply.

 

[Moralagos]

Processor: i5-3570k
MB: Asus Sabertooth Z77
Memory: Corsair Vengeance DD3 16 GB
Graphics: Sapphire Nitro RX 480 4 GB
HDD: Samsung HD103SJ 1TB F3 EcoGreen SATA 7200rpm 16MB
PSU: Corsair TX850M

 

[SgtScream]

The computer restarts? If so check both your cpu and gpu temps with MSI Afterburner's on screen display.

 

[Moralagos]

With some games, it restarts. With others, it doesn't. I'll check the temps, but I'm 100% positive that this isn't the issue. Like I said, the only thing different from when all the games worked fine is the new monitor. Also, there's no way the GPU and/or the CPU could instantly get super-hot to make the monitor go in sleep mode and the PC restart, just by launching a game. I very much doubt it has anything to do with temps.

 

[SgtScream]

With some games, it restarts. With others, it doesn't. I'll check the temps, but I'm 100% positive that this isn't the issue. Like I said, the only thing different from when all the games worked fine is the new monitor. Also, there's no way the GPU and/or the CPU could instantly get super-hot to make the monitor go in sleep mode and the PC restart, just by launching a game. I very much doubt it has anything to do with temps.

Yeah the new monitor can be placing more strain on your internal components. Check your temps. If everything works out, excuse my french "F--- LG" and make use of your return policy.