The monitor displays poor scan lines.
The monitor displays poor scan lines.
Your GPU only supports display ports, and the cable you're using is HDMI to DisplayPort. Your motherboard has an unused HDMI port. You might want to replace the cable—either use a standard HDMI to DisplayPort cable or connect directly to the motherboard via HDMI. The monitor should still work if it uses HDMI to HDMI, but it’s better to confirm the connection method for reliability.
There’s no direct method to connect HDMI>HDMI since there would be no output for a display (the cable is GPU>MOTHERBOARD with no screen connection). I’m not sure what the outcome would be, but that’s not the goal. Instead, try connecting the HDMI into your motherboard—especially if your CPU includes built-in graphics—and then use the display. It won’t be very fast for gaming, but it might help you check for streaks. If that doesn’t work, your GPU issue is likely the problem.
I purchased a fresh cable, but it didn't function. I'm wondering if the issue is with the monitor.
It's strange this display is only nine years old while your initial purchase was thirteen years ago.
It could be a monitor issue. You might purchase a replacement if the lines persist, returning the old one knowing it wasn't the cause. If the problem was there, just keep the new one!