Many older Samsung OEM boards have "Secure Boot" or "Legacy" settings that prevent modern UEFI-only graphics cards (like the RTX series) from booting. A BIOS update often improves this compatibility.
For most Samsung B75S1-based desktops, you should visit the Samsung Support website and search for your specific model number (e.g., DB400S3A). Download the utility. Samsung B75s1 Bios
A common issue with the Samsung B75S1 is the "Black Screen" when installing a new GPU. This is usually because the BIOS is set to mode, while new GPUs require UEFI . Many older Samsung OEM boards have "Secure Boot"
Ensuring the board properly recognizes "Ivy Bridge" (3rd Gen) CPUs if it originally shipped with a 2nd Gen chip. Samsung B75s1 Bios