My homebuilt pc wont start games without glitching out pls help me with troubleshooting

[shakr jr]

When i start up my homebuilt pc everything is alright untill i start up a game or go into fullscreen on a video, it starts glitching which looks like some pixels changing color back to the original blue red and green and a bit of purple and the game getting lower graphics (it all happens suddenly) and and the monitor (which is connected to my pc by hdmi) disconnects
I've tried troubleshooting but i cant find anything does someone know what to do and if so pls tell me

Ps. I'll send out a video off the problem if i can

 

[beman39]

sounds like 3 things, 1 being you don't have the correct drivers for your video card, so under load it spazzes out or 2) you don't have a good HDMI wire and it can't handle the output. try getting a DVI to HDMI connector or use a DVI only connection. or 3) your video card is taking a dump and is going to soon fry... also is your room very hot? make sure to keep your video card nice N cool by opening your side panel and putting a fan there to cool it off... ok that makes 4 things lol

 

[shakr jr]

First of all my room is cool enough and my videocard is at about 40 degrees celcius when it happens second of all thanks for replying so soon i'm going to see which one it is

 

[shakr jr]

And also wouldnt an full dvi connection connect it to the motherboard and not the videocard?

 

[beman39]

no dvi connects to the video card, like HDMI... its superior to HDMI...