This depends on the device, as enabling Falcon mode just removes loading the full version of u-boot.
Normal mode:
U-Boot SPL → U-Boot → Kernel
Falcon mode:
U-Boot SPL → Kernel
On some devices the full version of U-Boot is needed to initialize “all” peripherals, so while the Kernel will fully init everything, it may add extra delays into the kernel’s initialize time frame.
It “reduces” total boot time, from power on to login… Depending on device the “kernel” boot might be longer, but overall it should be shorter.
performance? Once you are booted up into the Linux Kernel there should be NO difference.
Regards,