Half of my monitor suddenly became covered in colorful RGB lines while I was using my PC. I can still move the mouse through the affected area, and changing HDMI cables made no difference. However, when I connect the same monitor to my Xbox, the display looks normal. What could be causing this, and how can I narrow down whether the problem is the graphics card, monitor port, or something else?
3 Answers
The graphics card is the most likely culprit, especially since the monitor works normally with the Xbox. Power the PC down, remove and reseat the GPU, then check that its power connectors are secure. If your processor has integrated graphics, connect the monitor to the motherboard's HDMI port and test again. If the lines disappear, the dedicated GPU is probably having trouble.
Try the simple isolation steps first: test another port on the monitor, another port on the graphics card, and a different display if you have one. Since two HDMI cables show the same problem and the Xbox is fine, the cable is unlikely to be the cause. A driver issue is also possible, so reinstalling or updating the graphics driver is worth trying after checking the hardware.
Reseating the GPU is a good first step, but if the artifacts remain under multiple ports or displays, the card may be failing. Memory or a bad RAM slot can occasionally cause strange visual behavior, though persistent colored lines isolated to the PC's video output point more strongly toward the GPU or its driver.
Before replacing the card, try a different output on the GPU and, if possible, another monitor. That can help rule out a damaged port or a display-specific issue.