Which Linux distro should I choose for gaming: Zorin OS, Kubuntu, or Linux Mint?

Don’t overthink the decision too much. Install one on the spare drive, use it for a few weeks, and learn how it works. Since these distributions are closely related, the basics will transfer easily if you later switch. You can also test them from a live USB or virtual machine first, but make sure the USB creation finishes successfully and verify the image if the flashing process fails.

All three should work with both NVIDIA and AMD graphics, so hardware compatibility probably shouldn’t decide this. In normal desktop use, the performance difference will be very small; your desktop environment, drivers, game compatibility, and system configuration will matter more.

Linux Mint uses Cinnamon, which is polished, familiar, and stable. It’s based on an Ubuntu long-term-support release, so software may not always be the newest, but updates tend to be predictable. Its driver manager is convenient for installing proprietary NVIDIA drivers.

Kubuntu uses KDE Plasma, which is highly customizable and generally current. It can be a good choice if you want newer software and lots of configuration options, though some people find the Ubuntu-specific packaging choices less appealing.

Zorin OS is also a solid option and offers a heavily customized desktop with several familiar layouts. It supports standard packages, Flatpaks, and Snaps, although having several package formats can sometimes be confusing. For your use case, Mint and Zorin should perform similarly, so choose the interface and software defaults you prefer.

Mint is probably the simplest recommendation here. Cinnamon feels complete, it has good documentation and community support, and it works well out of the box. Zorin is also based on Ubuntu and is polished, but it focuses more on providing a curated, familiar-looking desktop.

For gaming, neither Mint nor Zorin gives you a major automatic performance advantage. Use the recommended graphics driver, keep the system updated, and check whether your games work through Steam, Proton, or other compatibility tools. AMD graphics may be simpler on Linux because the drivers are usually integrated into the kernel and Mesa, while NVIDIA generally requires installing the proprietary driver.