Linux installer reboots after the distro logo on two different motherboards

The CPU could technically be involved, but it would be lower on my list until the simpler tests are done. Test the RAM, remove overclocks, try another power supply if available, and boot a known-good diagnostic or installer image. If other operating-system installers also reboot at the same point, that strongly suggests a hardware or firmware problem rather than Linux Mint itself.

Try simplifying the hardware while booting: use one RAM stick at a time, disable XMP/EXPO, reset the BIOS to default settings, and disconnect unnecessary drives and USB devices. If the processor has integrated graphics, remove the dedicated GPU and connect the monitor to the motherboard output. A faulty RAM stick, unstable memory profile, CPU, or power supply could cause a reboot right as the kernel starts.

Since the same failure happens with two motherboards, multiple USB drives, and different GPUs, the shared hardware or the installer media is more likely than the boards themselves. Re-download the Linux Mint ISO, verify its checksum, and recreate the bootable USB with a different imaging tool. It’s also worth testing another distribution or a Windows installer to see whether the system can boot other media.

Those motherboard models are commonly used with Linux, so compatibility with the boards themselves seems unlikely. Check the exact models on a hardware compatibility database, update to a current stable BIOS rather than repeatedly downgrading, and confirm that the boot mode is consistent—preferably UEFI. If the installer offers a safe graphics or compatibility mode, try that as well, since display initialization can sometimes cause an early reboot.