The black screen and colored pixels you are encountering may be due to a number of reasons, including graphics card driver issues, compatibility problems with the monitor, or even a hardware failure. Here are some steps you can try to resolve the issue:
Update your graphics card driver: Make sure you have the latest driver installed for your RX6950XT graphics card. You can download the latest driver from the AMD website.
Test your monitor: Try connecting your monitor to another computer or device to see if the problem persists. If it does, the problem may be with your monitor, and you may need to have it repaired or replaced.
Check for hardware problems: If the issue persists even when using a different monitor, the problem may be with your graphics card. You can try reseating the card, making sure it is securely connected to the power supply and the motherboard, and checking for any visible damage to the card or its components.
Disable overclocking: If you have overclocked your graphics card, try disabling overclocking to see if the problem persists. Overclocking can cause stability issues that can lead to black screens and other graphical problems.
Perform a clean install of the graphics card drivers: Uninstall the current driver and software, restart your computer, and then install the latest version of the driver and software.
If the problem persists after trying these steps, it may be necessary to seek technical assistance or repair for your graphics card.